Touch sensitive robotic gripper

ABSTRACT

A displacement measuring cell may be used to measure linear and/or angular displacement. The displacement measuring cell may include movable and stationary electrodes in a conductive fluid. Electrical property measurements may be used to determine how far the movable electrode has moved relative to the stationary electrode. The displacement measuring cell may include pistons and/or flexible walls. The displacement measuring cell may be used in a touch-sensitive robotic gripper. The touch-sensitive robotic gripper may include a plurality of displacement measuring cells mechanically in series and/or parallel. The touch-sensitive robotic gripper may be include a processor and/or memory configured to identify objects based on displacement measurements and/or other measurements. The processor may determine how to manipulate the object based on its identity.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Applicationswith Ser. Nos. 61/608,407 filed Mar. 8, 2012; 61/655,949 filed Jun. 5,2012; 61/673,114 filed Jul. 18, 2012; 61/683,324 filed Aug. 15, 2012;61/709,822 filed Oct. 4, 2012; and 61/767,130 filed Feb. 20, 2013, allof which are hereby incorporated by reference herein in their entirety.

TECHNICAL FIELD

This disclosure relates to displacement measuring cells that may be usedin robots and robotic grippers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B illustrate a touch sensor.

FIG. 2 illustrates an array of touch sensing cells.

FIGS. 3A-3C illustrate embodiments of grippers.

FIG. 4 illustrates a system for controlling the location and orientationof grippers.

FIG. 5 illustrates a gripping system that controls the closing,location, and orientation of grippers based on information from touchsensors.

FIGS. 6A and 6B are cross-section and side views of a touch sensorcomprising a sensor cell comprising a piston assembly.

FIG. 6C is a cross-section view of a touch sensor comprising a sensorcell including a bladder and a piston assembly.

FIG. 7 is a side view of a touch sensor comprising a plurality of pistonsensor cells arranged in parallel and series with one another.

FIGS. 8A and 8B are side views of a touch sensitive gripping systemcomprising a plurality of opposing touch sensor arrays.

FIG. 9 is a flow diagram of a method for calibrating a touch sensor andgrasping an object.

FIG. 10 is a cross-section view of a sensor array comprising a pluralityof electrodes, not separated by insulating walls.

FIG. 11 is an overhead view of a sensor array without internal,insulating walls.

FIG. 12A is a bottom view of a flexible substrate for a sensor arraywithout internal, insulating walls.

FIG. 12B is a front perspective view of an alternate embodiment of asensor array without internal insulating walls.

FIG. 13 is a cross-section view of a sensor array.

FIG. 14 is a schematic diagram of a sensor comprising control circuitryand a sensor array without internal, insulating walls.

FIG. 15 is a schematic diagram of a sensor comprising a controlmultiplexer and a sensor array without internal, insulating wallscomprising.

FIG. 16A is a schematic diagram of a relative permittivity sensorcomprising opposing sensor cells.

FIG. 16B is a schematic diagram of a resistivity sensor comprisingopposing sensor cells.

FIG. 17 is a schematic diagram of a gripper package comprising electricmotors in series with displacement sensors.

FIG. 18 is a side view of a quick-release gripping system with across-sectional view of a rotary joint.

FIG. 19 is a side view of a quick-change turret that may comprise arotary joint.

FIG. 20 is a cross-section view of a cam driven robotic gripper with acam guide for manipulating gripping sensor arrays.

FIGS. 21A and 21B are side perspective views of a robotic gripper whenside sensor array panels are in a flat position.

FIGS. 22A and 22B are side perspective views of the robotic gripper whenthe side sensor array panels are perpendicular to the bottom sensorarray panel.

FIG. 23 is a side perspective view of the robotic gripper when the sidesensor array panels are in an acutely angled position.

FIGS. 24A and 24B are cross-section views of skin panels configured topower a robot, such as a robotic gripper or the like.

FIG. 25 is a cross-section view of a skeletal component comprising aplurality of integrated batteries.

FIGS. 26A and 26B are front perspective views of different types ofbattery windings.

FIGS. 27A-27C are cross-section views of sections of the inner battery.

FIG. 28 is a front perspective view of a battery comprising a heatingelement.

FIGS. 29A and 29B are front and top perspective views of a rotationalhydraulic joint.

FIGS. 29C and 29D are front perspective views of the piston and the endcap that may be used in a rotational hydraulic joint.

FIGS. 29E-29H are cross-section views of the center and outer shafts andthe rotational hydraulic joint assembled therefrom.

FIGS. 30A and 30B are cross-section views of additional rotationalhydraulic joint embodiments.

FIG. 31 is a schematic diagram of a mechanical joint rotated by a linearhydraulic cylinder.

FIG. 32 is a schematic diagram of a plurality of sensors coupled by aplurality of mechanical joints to form a robotic finger.

FIGS. 33A-33C are side perspective views of various configurations of arobotic finger formed from a plurality of sensors coupled by a pluralityof joints.

FIG. 34 is a front perspective view of a robotic hand comprising aplurality of fingers.

FIG. 35 is a front perspective view of an end cap that may be coupled toan inner core.

FIG. 36 is a front perspective view of a skeletal component with a maleend and a female end.

FIG. 37 is a schematic diagram of a compound ball joint with threedegrees of freedom.

FIG. 38 includes top, front, and side perspective views of a compact,compound joint.

FIG. 39 is a schematic diagram of an arm including a plurality of jointswith multiple degrees of a freedom and a plurality of skeletalcomponents.

FIG. 40 is a schematic diagram of a robotic foot configured to providemobility and balance.

FIGS. 41A and 41B are a flow diagram of a method for walking using therobotic foot.

FIG. 42 is a schematic diagram of a complete skeleton system for arobot.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Robotic systems have become increasingly common in automatedmanufacturing. Some such systems comprise what are known as end effectgrippers. Robotic systems including end effect grippers often manipulatean object to a desired location. In many instances, it is critical forproper assembly or fabrication that the object be placed exactly in thedesired location. However, known gripping systems are only able toaccurately manipulate an object to a desired location if that object isinserted into the gripper at a precise location. This requires that theobject be manually positioned and the gripper be manually closed aboutthe object. The manual positioning and closing requires additional timeand labor.

A gripping system may use sensors and one or more processors to generatea more sophisticated understanding of an object being grasped by thegripping system. The processor may include a general purpose device,such as an Intel®, AMD®, or other “off-the-shelf” microprocessor. Theprocessor may include a special purpose processing device, such as anASIC, SoC, SiP, FPGA, PAL, PLA, FPLA, PLD, microcontroller or othercustomized or programmable device. In some embodiments, the processormay be comprised of more than one general purpose device and/or specialpurpose device. The gripping system may also include a memory containinginstructions or data. The memory may include static RAM, dynamic RAM,flash memory, ROM, CD-ROM, disk, tape, magnetic, optical, or othercomputer storage media. In some embodiments, the processor and/or memorymay control multiple gripping systems and/or receive measurements fromsensors. The gripping systems may be connected to the processor andmemory by wires, a wired or wireless network, or other means ofcommunication.

Touch Sensor

FIG. 1A illustrates a single touch sensor 100 that may be used todescribe an object being grasped by a gripping system. The sensorcomprises a sensing cell 110 that contains a stationary electrode 120and a movable electrode 130. The sensing cell 110 is filled with aconductive fluid 112. The conductive fluid 112 may convey charge betweenthe electrodes 120, 130 to prevent a potential difference between theelectrodes from causing an accumulation of charge. A dielectric fluidmay optionally be used instead of a conductive fluid. Dielectric andconductive fluids may be referred to as electrically operative fluids. Apower source 140 is connected to the two electrodes 120, 130 to form acompleted circuit through the conductive fluid.

The movable electrode 130 is capable of changing position relative tothe stationary electrode 120. When an object presses against the touchsensor, the movable electrode 130 will be pushed towards the stationaryelectrode 120. As the movable electrode changes position, the resistanceand other properties of the circuit will change. The resistance isdependent on the distance between the electrodes 120, 130. When thedistance between electrodes 120, 130 is largest, the resistance of thecircuit will be at a maximum. For many conductive fluids 112, therelationship between distance and resistance will be approximatelylinear. Alternatively or in addition, a capacitance between theelectrodes may change as the distance between the electrodes changes. Anelectrical property measuring device 150 may be used to measure thechanges in properties of the circuit as the movable electrode 130changes position. The measurements from the electrical propertymeasuring device 150 may be used to determine the distance betweenelectrodes 120, 130.

Many different types of electrical property measuring devices 150 andconfigurations of the circuit are possible. In the illustratedembodiment, the power source 140 is a constant voltage source and theelectrical property measuring device 150 is an ammeter in theconfiguration illustrated. However, the touch sensor 100 could bereconfigured to have a constant current power source and a voltmeter setup in parallel with the sensing cell 110. An ohmmeter could be used asboth the power source and the measuring device. A resistor or othercircuit component could be placed in parallel or series with the sensingcell 110, which would allow an ammeter to be used with a constantcurrent source or a voltmeter to be used with a constant voltage source.A voltmeter could measure the voltage drop across a series resistor todetermine the electrical properties of the sensing cell. For a circuitwith a changing capacitance, a capacitance meter could be used tomeasure the capacitance, and/or the capacitor voltage, capacitorcurrent, and/or capacitor impedance could be measured. The power sourcemay supply direct current or alternating current. The power source mayalso apply power at regular sampling intervals or have a duty cycle ofless than 100%. Those of skill in the art will recognize other possiblecircuits that would allow an electrical property measuring device 150 tomeasure changes in the position of the flexible, movable electrode. Anymeasurement of voltage, current, or resistance can be converted toanother measurement using Ohm's law of V=IR. For more complicatedsystems, Kirchhoff's circuit laws may also be needed to perform theconversion.

Many different kinds of conductive fluid 112 are possible includingwater mixed with sodium chloride, calcium chloride, or any other saltthat creates an electrolyte when mixed with water; vinegar; gallium;gallium alloys; wood's metal; gallium aluminum alloy; sodium potassiumalloy; and sulfuric acid. In general, the conductive fluid 112 maycomprise any salt, acid, and/or base. Non-toxic antifreeze, such aspropylene glycol or glycerol, and/or toxic antifreeze, such as ethyleneglycol may be added to water-based conductive fluids. Many conductivefluids are commercially available including: Indium Corporation'sGallium Alloy 46L with a melting point of 7.6 degrees Celsius;Rotometal's Gallinstan with a melting point of −19 degrees Celsius.These metals become liquid at warm temperatures and offer highconductivity. Potassium chloride is available commercially from sources,such as Cole-Parmer KCL 3M with saturated AgCl. The choice of conductivefluid 112 may depend on the cost, safety, and precision desired. Galliumalloys and sodium potassium alloy may be expensive. Sodium potassiumalloy reacts violently with air when heated, but then forms an oxidecoating that inhibits further reaction. Gallium aluminum alloy reactsviolently with water releasing hydrogen gas and does not have anyinhibiting activity. Additionally, the choice of conductive fluid 112will affect the requirements of the power source 140 and electricalproperty measuring device 150. A highly conductive fluid may consumemore energy unless a low voltage source 140 is used. A more resistivefluid may consume more energy when a constant current source is used. Amore sensitive electrical property measuring device 150 may also berequired for more highly conductive fluids.

The electrodes 120, 130 comprise flat plates in the illustratedembodiment. Wires 122, 132 connect the flat plates with the power source140 and electrical property measuring device 150. The electrodes 120,130 may be made of conductive material such as copper, silver, aluminum,or any other conductive material known in the art. The size of theelectrodes 120, 130 will depend on the size and geography of the objectto be grasped by the gripping system. For very small or complicatedobjects, the flat plates may have a surface area on the order of 10̂-4square inches.

FIG. 1B illustrates the structure of the sensing cell 110 in moredetail. The movable electrode 130 is attached to a flexible silicon wall114. The remainder of the sensing cell wall 116 is made from a thermosetor thermoplastic, a flexible wire cable, an elastomer, such as siliconrubber, or the like. The stationary electrode 120 further comprises abaffle 160 that allows the conductive fluid 112 (or a dielectric fluid)to escape into reservoir 170 as the movable electrode 130 is compressedtowards the stationary electrode 120. A pressure controller 180 mayallow the conductive fluid 112 to escape into the reservoir 170 when themovable electrode 130 is compressed. The pressure controller 180 forcesthe conductive fluid 112 back into the sensing chamber 118 when themovable electrode 130 is no longer compressed. The conductive fluid 112may be incompressible to prevent compression of the movable electrodefrom changing electrical properties of the conductive fluid.

In this embodiment, the pressure controller 180 may comprise a metalplate 182 and a mechanical spring 184 that applies pressure to the metalplate 182 in accordance with Hooke's law. A silicon layer 186 may beaffixed to the metal plate 182. Alternatively, the silicon layer 186 mayact as a mechanical spring without the metal plate 182. The siliconlayer 186 may seal the back end of the reservoir 170 from possible leaksor loss of conductive fluid 112. In other embodiments, a hydraulic orpneumatic spring may be used in place of the mechanical spring 184. Themechanical spring may be a simple elastomer spring effect, a fluid flowcontrolled by a pressure regulator, or the like. The pressure controller180 may also comprise a pressure measuring device and/or pressureregulating device that determines the pressure of the conductive fluid112. The pressure measuring device may measure the movement of the metalplate 182 and/or the silicon layer 186, or the pressure measuring devicemay use other methods known in the art to determine the pressure of theconductive fluid 112. The pressure controller 180 may comprise apiezoresistive pressure transducer (not shown) in contact with the metalplate 182, the silicon layer 186, and/or the flexible walls 114. Thepiezoresistive pressure transducer may be attached to the metal plate182 and in contact with the silicon layer 186. The piezoresistive sensormay be used to measure shear forces on the cell. In some embodiments,the pressure may be determined by measuring the in-line pressure of thehydraulic system.

Materials besides silicon may be used for the flexible wall 114 in otherembodiments. The flexible wall may conform to the structure of theobject being grasped and may be nonconductive. Suitable materials mayinclude latex, plastics, natural and synthetic rubbers, and silicones.Because the flexible wall 114 will be used to grasp the object, thematerial for the flexible wall 114 may be selected to have a highcoefficient of friction with the object intended to be grasped. In someembodiments, it may also be desirable that the movable electrode 130 beflexible as well. In those embodiments, the movable electrode maycomprise conductive polymers, such as conductive or doped silicon orfluorosilicone. Alternatively, metal electrodes may be used where themetal electrode is thin enough to flex, or the metal electrode has asmall enough surface area to contour to the surface of the object beinggripped.

Sensor Array

FIG. 2 illustrates an array of sensing cells 200 that may be used tomeasure the different areas of an object pressing the individual sensingcells 210 a,b,c,d. Each sensing cell 210 a,b,c,d in the array isconnected to its own electrical property measuring device 250 a,b,c,d.The illustrated array 200 will produce a two dimensional set ofmeasurements of the object touching the array 200. The array 200 candetect the length of the object and the length of various components ofthe object and the depth of the object and the depth of variouscomponents of the object. By stacking additional sensor cells on top ofor below the array 200 (into or out of the figure), an array could becreated that will create a three dimensional set of measurements of theobject. The width of the object and the width of various components ofthe object may be detected in this configuration. Whether an arraysensing two dimensions or three dimensions is used will depend on theapplication of the gripper. Also, depending on the sensing needs, thearray may contain very few sensors or may contain many thousands ofsensors.

Each sensing cell 210 a,b,c,d comprises a baffle 260 a,b,c,d and areservoir 270 a,b,c,d. As shown in this embodiment, the stationaryelectrodes 220 a,b,c,d may be separate from the baffles 260 a,b,c,d. Themovable electrodes 230 a,b,c,d may be attached to a flexible wall 214.In this embodiment, the sensing cells 210 a,b,c,d are separated fromeach other by the thermoset, thermoplastic, or elastomer walls 216. Inother embodiments, conductive fluid 112 may be allowed to flow betweenreservoirs 270 a,b,c,d or a common reservoir may be shared by all thesensing cells 210 a,b,c,d. Additionally, embodiments may have sensingchambers 218 a,b,c,d not separated by the thermoset or thermoplasticwalls 216. However, this may create cross conductivity between movableelectrodes 230 a,b,c,d and stationary electrodes 220 a,b,c,d indifferent sensing cells 210 a,b,c,d. In some embodiments, a single platemay comprise the stationary electrodes 220 a,b,c,d or the stationaryelectrodes 220 a,b,c,d may be electrically coupled with one another. Inthese embodiments, the electrical property measuring devices 250 a,b,c,dand circuits may be configured to measure an electrical property of asingle movable electrode 230 a,b,c,d. For example, ammeters may beplaced between the power source 240 and the movable electrodes 230a,b,c,d rather than between the stationary electrodes 220 a,b,c,d andthe power source 240.

Grippers

FIGS. 3A, 3B, and 3C illustrate various embodiments of grippers that maycomprise sensor arrays 200. Grippers may have two 310, three 320, orfour 330 gripping members. Those of skill in the art will recognize howto make grippers comprising more than four gripping members. In someembodiments, a sensor array 200 may be placed on the inside, outside, orboth inside and outside of a preexisting gripping member depending onthe gripper's function. For those grippers meant to grasp the outside ofan object, the sensor arrays 200 may be placed on the inside of thegripping members. For those grippers meant to grasp an object from theinside, for example grabbing a container or bottle from the inside, thesensor arrays 200 may be placed on the outside of the gripping members.In other embodiments, the gripping member is formed entirely from thesensor array 200 with the flexible wall 214 and thermoset orthermoplastic walls 216 defining the shape and structure of the grippingmember. The movable electrodes 230 a,b,c,d are located on the side ofthe gripping member that is meant to come in contact with the objectbeing grasped. For gripping members that may contact objects on bothsides, sensing cells 210 a,b,c,d may face both directions. In otherembodiments, a single sensing cell may have a stationary electrode withmovable electrodes on each side of it.

For a gripper with two gripping members 310, half-cylindrical grippingmembers 312, 314 may provide more contact area with the object beinggrasped. In other embodiments, the two gripping members may each beflat, one may be flat with the other half-cylindrical, or they may beany other shapes that would maximize contact area with the object beinggrasped. The shape will depend on the particular object to be grasped. Agripper with three gripping members 320 may be configured such that thegripping members 322, 324, 326 are flat and approximately form the sidesof a triangle. The triangle may be equilateral, isosceles, or obtuse.For any triangle, at least two of the angles formed between the grippingmembers will need to be acute. The gripping members 322, 324, 326 mayalso be shapes other than flat depending on the object to be grasped.Similarly, a gripper with four gripping members 330 may have flatgripping members 332, 334, 336, 338 that approximately form the sides ofa square. However, it 330 may also form other quadrilaterals and mayhave gripping members 332, 334, 336, 338 that are shapes other thanflat. Those of skill in the art will recognize other shapes includingthree dimensional shapes, for example a hemisphere, that may beapproximately formed by the configuration of a given number of grippingmembers. Any of the above described embodiments of gripper members,whether round, triangular, or square, can have one or more additionalmembers (not shown) that can move perpendicular relative to the movementof the gripping members. The additional members may then move inside thesquare, triangular, or round shapes to measure the dimensions of theobject from a third axes in order to create a more completethree-dimensional profile of the object being grasped. The additionalmembers would enter between the two members 312, 314, three members 322,324, 326, or four members 332, 334, 336, 338 shown in FIGS. 3A, 3B, and3C, respectively.

The gripping members 312, 314 are designed to be moved relative to oneanother so that they 312, 314 may grasp an object. When the grippingmembers 312, 314 are closest to each other or grasping an object, thegripper 310 may be described as closed. When the gripping members 312,314 are furthest from each other, the gripper 310 may be described asopen. Actuators controlling the position of the gripping members 312,314 may open and close the gripper 310. Also, dowel rods and guide pinsmay control the path of the gripping members 312, 314 to ensure thatthey are aligned correctly. High precision guide pins may be used whenvery accurate positioning is required. The actuator movement may beaccomplished with pneumatic, hydraulic, or electric motors or othermeans known in the art. An electric motor and lead screw may be used toproduce linear actuation of the gripping members 312, 314.

In addition, the gripper may be controlled by actuators that change thelinear position of the gripper among a three dimensional space.Additional actuators may also allow rotation of the gripper along one ormore axes. These actuators may precisely control the movement of thegripper and object being grasped to allow for high precision assembly,fabrication, insertion, manufacturing, surgery, measurement or otherknown uses for automated grippers.

Gripping Systems

FIG. 4 illustrates a system 400 for manipulating one or more grippers410, 440 after at least one gripper 410 has closed on an object.Although two grippers 410, 440 are shown in this embodiment, the secondgripper 440 may be replaced by other tools known in the art such astools for drilling, milling, powder coating, assembly, or otheroperations. In this embodiment, the gripper 410 grasping the object maybe moved along the X and Z axes. Actuators 420, 430 (e.g., servos) mayuse lead screws 422, 432 to control the movement of the gripper 410along these axes.

The second gripper 440 may move only along the Y axis and may becontrolled by an actuator 450 and lead screw 452. Another actuator (notshown) may also rotate the second gripper 440 about the Y axis. This mayallow for an object held by the first gripper 410 to be screwed into anobject held by the second gripper 440. Even though, in the illustratedembodiment, each gripper 410, 440 is only limited to movement along someaxes, the grippers 410, 440 may move relative to each other along allaxes. Thus, the system 400 can correct for offsets in location along theX, Y, or Z axes. In other embodiments, each gripper 410, 440 may be ableto move along all the axes and rotate about all the axes. In someembodiments, the second gripper 440 is a conventional gripper and thefirst gripper 410 is a touch sensitive gripper. Other “off-the-shelf”robotic systems may be used that control the gripper with 4 to 6 axes ofmanipulation. Exemplary “off-the-shelf” systems include the Kuka AG's KRseries, or manipulators, such as Fanuc Robotics Industrial Robots, maybe incorporated into the gripper actuation. Robotic systems, such as theFanuc M-1iA, may incorporate movement of a single gripper into a threemotor x-y-z axis control system. An alternative control scheme may use asingle hydraulic motor to control three hydraulic joints.

FIG. 5 illustrates a touch sensitive robotic gripping system 500 with aprocessor 510 for controlling the system. The gripping system 500 may bea component of a complete robotic system (not shown), which may includevision systems, proximity detection, safety shut-off, computerintegration, programmable logic controllers (PLCs), LIDAR, computergeographic modeling, and/or robotic arms. The complete robotic systemmay be autonomous, semi-autonomous, or operator controlled. In theillustrated embodiment, a hydraulic system 520 is controlled by theprocessor 510 with wire 516. The hydraulic system 520 may be used toopen and close the grippers 410, 440, regulate pressure on reservoirs270 collectively or individually, regulate pressure control valves, andcontrol direction fluid valves. The pressure and fluid control valvesmay be regulated using pulse width modulation. The electrical propertymeasurements and pressure measurements may be sent from the grippers410, 440 to the processor 510 over wires 511, 514. The processor 510also may control the actuators 420, 430, 450 using wires 512, 513, 515,which allows the processor 510 to modify the location of the grippers410, 440. Alternatively, the actuators 420, 430, 450 may be linear orradial hydraulic actuators and the wires 512, 513, 515 may controlpressure and fluid directional valves. In other embodiments, theprocessor 510 may control components and receive measurements wirelesslyor through other known methods of communication.

The processor 510 may receive sampled and quantized measurement dataregarding the object that it is gripping from electrical propertymeasuring devices 250 a,b,c,d, and pressure measurement devices in eachgripping member 410, 440. Shear sensors (not shown) and temperaturesensor (not shown) in each gripping member 410, 440 may sendmeasurements to the processor 510. The processor 510 may convert thissampled data into a geographic model of the object being grasped. Theprocessor 510 may compare this model with a diagram of the object storedin a memory. Objects may be recognized by comparing geographic shapesand/or blueprints stored in the memory to measured dimensions and/orcomputer generated geographic shapes of grasped objects. In anembodiment, one or more neural networks may perform the comparison.Geographic shapes of objects may be stored along with operations thatmay be performed with these shapes. Objects may be compared to twoand/or three dimensional prints and/or representations stored in thememory by design programs, such as AutoCAD. Then the processor 510decides how to properly manipulate the object using the actuators 420,430, 450 based on this information.

The raw measurement data may be sampled and quantized before it istransferred to the processor 510. The rate of sampling may depend onwhat the gripping system 500 is being used for. The raw measurement datamay be sampled many thousands of times per second when the manner inwhich the object is grasped is important. Whereas if the orientationonly needs to be determined once, the processor 510 may sample only afew times per second or once per object being grasped. The time for theprocessor 510 to manipulate the sampled data may also determine howoften the raw measurement data is sampled. The processor may only samplethe measurement data when it is has completed the previous calculationand is ready to perform another calculation. In some embodiments, thegrasping of an object may cause one or more movable electrode 230 totilt at an angle to the stationary electrodes 220. As a result, themeasured distance between electrodes 220, 230 may increase as theelectrodes 230 tilt. A higher sampling rate may be required inembodiments and/or configurations where tilting is possible to enable tothe processor to detect and correct for tilt error. In some embodiments,the pressure measurement data and electrical property measurement datamay be sampled at different rates.

The number of bits per sample (quantization) will also depend on theapplication of the gripper system. For more precise measurements orsystems where a wide fluctuation in measurements is possible, 32, 64, orhigher bit samples may be required. The quantization rate may also belimited by the sensitivity of the measuring devices 250. For lesssensitive measuring devices, there may be little or no benefit to usingmore than 16 or 8 bits per sample. In some embodiments, the measuringdevices 250 may perform the sampling and quantization as part of themeasurement process. In other embodiments, the processor 510 or anothercomponent performs the sampling and quantizing. The sampled andquantized measurement data may be stored in the memory.

For the processor 510 to convert the sampled measurement data into ageographic model of an object, the processor 510 may first calibrate themeasurement data to displacements. In some embodiments, the sampledelectrical property measurements (e.g., voltage, capacitance, current,resistance, impedance, etc.) may be converted to displacementmeasurements by moving the movable electrodes 230 to a known distance sothe processor can determine the value of the electrical propertymeasurements received at that distance. A set of data points may begenerated by measuring the electrical property across a series ofdisplacements separated by known increments (e.g., separated byequidistant increments). The processor may create a linear fit for theentire set of detected calibration values or it may create a linearinterpolation between each pair of detected values. In otherembodiments, a non-linear function may be used to fit the detectedcalibration values or interpolate between detected values. A set ofdiscrete data points, a fit for the data points, and/or one or moreinterpolations for the data points may be referred to as an electricalproperty measurement to displacement curve. Alternatively, to calibratethe gripper, a flat object or object shaped similarly to the grippingmember may be slowly closed upon by the gripper. The processor 510 mayuse the information received from this process to map electricalproperty measurements to a linear distance scale with arbitrary units,and/or a distance to voltage scale may be created. Each measurement maybe mapped to a discrete value. The number of steps used by the processor510 when quantizing the electrical property measurements may depend onthe distance and measurement increments. The minimum discrete increment(e.g., minimum step) may be selected to correspond to a desireddisplacement measurement resolution. For example, to measure a distanceof 0.750 inches with an accuracy of 0.001 inches, the processor 510 maysubdivide the voltage range into 750 quantized steps with each stepcorresponding to a 0.001-inch increment. The processor 510 may calibrateeach sensor cell 210 individually, or it 510 may use an averagecalibration for all sensor cells 210. In some embodiments, a temperaturesensor may allow the processor 510 to further calibrate for thetemperature of the conductive fluid 112. The temperature sensor may bein contact with the movable electrode, stationary electrode, thechamber, a portion of the chamber near a contact surface, fluid lines,and/or fluid reservoirs to determine fluid temperature. The electricalproperty measurement to displacement curve may take temperature as aninput and output a temperature-corrected displacement. Alternatively, orin addition, the processor 510 may be configured to make predeterminedcorrections to the electrical property measurement to displacement curvebased on temperature variations from a calibrated temperature, and/orcalibration may include determining a plurality of electrical propertymeasurement to displacement curves for different temperatures. Thetemperature measurements may be used to adjust the electrical propertymeasurements input to the electrical property measurement todisplacement curve and/or to adjust the displacement computed from theelectrical property measurement to displacement curve.

A diagram of the object to be grasped may be stored in a memoryaccessible by the processor 510. The diagram may be created by anAutoCAD design program. An object may be stored in the memory inmultiple ways. Measurements or other data about the size and shape ofthe object may be directly loaded into the memory by a user or anothercomputer system. Alternatively, the gripper 410 may be manually closedon the object one or more times with the object set at a differentpredefined orientation each time. Further, if the gripper 410 and/orpressure controller 180 is controlled using hydraulic or pneumaticmeans, the pressure exerted by the gripper 410 and/or the pressure ofthe conductive fluid 112 may be adjusted manually. The processor 510then generates a diagram of the object based on the measurements fromthe sensor array 200. The diagram may then be stored in the memory bythe processor 510.

Once the processor 510 has been calibrated and a diagram and/or shapehas been stored in the memory, the gripping system 500 may startmanipulating objects. Objects may be fed to the gripper 410 with avibrating hopper machine, conveyor belt, or other means known in theart. An optical, vision, and/or acoustic system may detect the locationof the object to be grasped. The object may also or instead trigger amicroswitch alerting the gripping system 500 to the presence of theobject. The processor 510 may then move the gripper 410 to the expectedlocation of the object and attempt to grasp the object. Once the gripperis in the proper location, the processor 510 may close the gripper 410on the object. If the object is fragile or only a limited pressure maybe applied to the object, the processor 510 may monitor pressuremeasurements and/or electrical property measurements to determine howfar to close the gripper 410 on the object. The processor 510 may alsomonitor the electrical property measurement data received fromindividual sensing cells 210 in some embodiments. If the electrodes 220,230 are too close or touching, a sensing cell may draw too much currentand damage or drain the power source 240. The processor stops closingthe gripper 410 if the electrodes 220, 230 of any sensing cell 210 aretoo close. In other embodiments, the circuit may be designed to preventtoo much current draw or a porous insulating material may be placed inthe sensing cell 210 that allows the conductive fluid 112 to flow butprevents the electrodes 220, 230 from touching.

When the object is grasped, it is in an unknown position andorientation. The processor 510 then uses the data from the electricalproperty measuring device to create a geographic model of the object. Insome embodiments, the processor 510 may create several geographic modelsof the object as it is being grasped. In other embodiments, theprocessor 510 may create only a single geographic model of the objectonce the gripper 410 has finished closing on the object. The processor510 may create the geographic model by converting the sampled data intodisplacements, detecting edges and boundaries between wider and thinnerportions of the object, placing sampled data directly into an array, orusing any other known means to describe an object. The type ofgeographic model generated by the processor 510 may depend on the typeof diagram saved in the memory. The geographic model may be defined in amanner that simplifies comparison with the diagram saved in the memory.

Various methods may be used to compare the diagram in the memory withthe geographic model of the object generated by the processor 510 todetermine the orientation and position of the object. If the modelcomprises edges and boundaries, the processor 510 may try to align thoseedges and boundaries with diagram features. For distances, the processor510 may try to match those distances with anticipated or measureddistances in the diagram. To find a match, the processor 510 may attemptto minimize the mean square error between the geographic model and thediagram; it 510 may attempt to minimize the maximum error between anypoint in the geographic model and the corresponding point in thediagram; or it 510 may use any other method known in the art ofminimizing error. In some embodiments, the processor 510 will determinethat a match could not be found if the error cannot be reduced below acertain threshold or confidence level. The processor 510 may attempt todrop the object and grasp it again or send a signal to a human operatorif a match is not found.

If a way to match the model to the diagram is found, the processor 510then determines the manipulations required to make the geographic modelmatch a desired orientation and location stored in the memory. In someembodiments, the diagram comprises the desired orientation and location.In other embodiments, the desired orientation and location are storedseparately. The object may not be centered in the gripper, so theprocessor 510 will need to compensate for the offset of the object. Theobject may also be rotated along one or more axes relative to thediagram. The processor 510 may then rotate the grippers 410, 440 andmove the grippers 410, 440 laterally until the object is in the properposition using the actuators 420, 430, 450.

In some embodiments, a touch sensitive gripper may place the object in aconventional gripper that requires precise placement of the object. Inother embodiments, the corrections may occur during the normal movementof the grippers 410, 440, if the grippers 410, 440 are required to movethe object as part of the grippers' 410, 440 function. In someembodiments, the processor 510 may be trained as to the properorientation and location for the object as well as the proper movementof the object through manual movement of the grippers 410, 440 andactuators 420, 430, 450. The processor 510 then saves this informationto the memory. In some of these embodiments, the processor 510 mayexactly follow the movements taught to it. In other embodiments, theprocessor 510 may be instructed to save one or a few locations andorientations and it uses the most efficient movement to progress to eachlocation and orientation. In still other embodiments, the processor 510may perform an activity such as screwing a bolt or moving in a sawingmotion once it reaches a desired location and orientation. Once theactivity is complete, the processor 510 may repeat the process again.Each repetition may be referred to as a cycle. The processor 510 may beprogrammed to perform a predetermined number of cycles.

Diagrams of several different types of objects may be stored in thememory at a single time. The processor 510 may attempt to match anobject being grasped against all the diagrams in the memory. Theprocessor 510 may be programmed using computer code in the memory toperform different functions based on the object detected. The processor510 may be instructed to assemble different objects held in differentgrippers 410, 440 together. In an embodiment, the processor 510 sortsobjects into different locations based on the type of object detected.In other embodiments, the processor 510 may be designed to cycle througha series of different tasks for the same object. In the manufacturingcontext, grippers 410, 440 may have multiple locations to insert boltsand/or to fabricate, weld, and/or assemble components. The processor 510may have the grippers 410, 440 insert a bolt into, or perform anothermanufacturing operation at, each location before beginning again at thefirst location. The processor 510 may attempt to find a correct part byhaving the grippers 410, 440 grasp multiple objects and release thosethat do not match the desired object. The processor 510 may move thegrippers 410, 440 randomly or systematically after it releases anincorrect object and attempts to find a new object. Common sensors, suchas piezoresistive, capacitive proximity, inductive, optical, infrared,ultrasonic, laser, or Merkel tactile cells, may assist in sensing theobject and/or in the manufacturing operation. Additional sensors may belocated on or off the grippers.

Sensor Cell Comprising a Piston

FIGS. 6A and 6B are cross-section and side views of a touch sensor 600 acomprising a sensor cell 610 a that uses a piston assembly. The pistonassembly comprises a piston rod 691 a, which is affixed to a piston 690a and a contact head 695 a that contacts an object of interest. Thesensor cell comprises two chambers: a piston extension chamber 692 a anda piston retraction chamber 694 a. In the illustrated embodiment, eachchamber 692 a, 694 a contains a conductive fluid 612 a that can be addedto or removed from the chamber 692 a, 694 a via one or more reservoirs(not shown) and pumps (not shown). Alternatively, a dielectric fluid maybe used. The pumps (not shown) extend or retract the piston 690 a byadding or removing fluid. In other embodiments, one chamber may comprisea fluid, while the other does not and/or there may be only one pump,and/or a bidirectional valve may or may not be used. A positivedisplacement pump may be used to increase the precision of the movement.A positive displacement pump may be able to move a fixed amount of fluidthat corresponds to a linear displacement of a piston in a single and/ormultiple hydraulic cylinders.

The sensor cell 610 a may further comprise a stationary electrode 620 aat a proximal end of the sensor cell 610 a and a movable electrode 630a. The movable electrode 630 a may be affixed to the piston 690 a. Thisconfiguration may allow the electrodes 620 a, 630 a to measure thedistance moved by the piston 690 a during extension or retraction. Bothelectrodes 620 a, 630 a are in the extension chamber 692 a in theillustrated embodiment, but they could also or instead be placed in theretraction chamber 694 a in other embodiments. Both electrodes 620 a,630 a may be insert molded into the end cap and piston, respectively, toprevent leaking through the lead wires of the electrodes.

The illustrated electrodes 620 a, 630 a are flat plates. The electrodes620 a, 630 a may be made of conductive material such as copper, silver,gold, aluminum, silver chloride, tungsten, tantalum, columbium,titanium, molybdenum, gallium, conductive ink, or the like. Theconductive fluid 612 a may comprise a salt, such as sodium chloride,calcium chloride, potassium chloride, or the like, dissolved in water;vinegar; gallium; wood's metal; gallium alloys, such as gallium aluminumalloy or eutectic gallium-indium alloy; sodium potassium alloy; orsulfuric acid. Non-toxic antifreeze, such as propylene glycol orglycerol, and/or toxic antifreeze, such as ethylene glycol may be addedto water-based conductive fluids. The conductive fluid 612 a may alsocomprise a material similar to the electrodes 620 a, 630 a to preventleaching. For example, the conductive fluid 612 a may be potassiumchloride saturated with silver chloride for silver or silver chlorideelectrodes 620 a, 630 a. Some very corrosive conductive fluids 612 a,such as gallium-indium alloy or other liquid metals, may dissolve mostmetals. The electrodes 620 a, 630 a may comprise a material with a highresistance to corrosion, such as tungsten or tantalum, or a materialresistant to corrosion, such as columbium, titanium, or molybdenum, inthose embodiments. In some embodiments, fluid in the chamber 692 a, 694a not containing electrodes 620 a, 630 a will be non-conductive. Inother embodiments, both chambers 692 a, 694 a will share a commonreservoir containing the conductive fluid 612 a. As before, theelectrodes 620 a, 630 a may be powered by alternating or direct current.

The walls 616 a, piston 690 a, and piston rod 691 a may be made from anonconductive material such as polycarbonate, other hard polymers, orthe like. In some embodiments, the walls 616 a may be a conductivematerial, such as titanium, steel, aluminum, or the like, covered with alayer of nonconductive material or a sleeve of nonconductive material toinsulate them from the electrodes 620 a, 630 a. Because materials likesilver chloride decompose when exposed to ultraviolet (UV) or otherspecific frequencies of light, the walls 616 a may comprise a materialthat blocks UV light or light of other specific frequencies. Forcorrosive conductive fluids 612 a, the walls 616 a may be selected to bea polymer or a metal that is resistant to corrosion.

Additionally, the walls 616 a may be selected to be a material resistantto damage from external elements. This may allow the sensor cell 610 ato come in contact with hazardous materials. The sensor cell 610 a mayeven be inserted into oil filled cylinders such as are used in theconstruction equipment industry for bulldozers and the like. The sensorcell 610 a can range in size from very small, such as nanofabricatedsensor cells, to very large, such as multiple meters in width or lengthor larger, depending on the selected application.

In the illustrated embodiment, wires 622 a, 632 a are coupled to theelectrodes 620 a, 630 a, and the wire 632 a passes through theretraction chamber 694 a and out of the distal end of the sensor cell600 a. In other embodiments, the wire 632 a passes through the extensionchamber 692 a and the proximal end of the sensor cell 600 a. Inembodiments where parts of the piston 690 a, piston rod 691 a, and walls616 a are conductive, these elements may act as a portion of the wire632 a. The wire 632 a of the movable electrode 630 a may run through thecenter of the piston 690 a to make an external connection.

The wires 622 a, 632 a may be powered by a power source (not shown) andconnected to an electrical property measuring device (not shown) like intouch sensor 100. The electrical property measuring device measureselectrical characteristics corresponding to the distance the piston 690a is extended and may comprise a current shunt, a Wheatstone bridge, orthe like. The touch sensor 600 a may comprise additional measuringdevices, such as a piezoresistive pressure sensor (not shown) and/or apolyvinyl idene fluoride (PVDF) film sensor (not shown). Thepiezoresistive pressure sensor may be placed in one or both chambers 692a, 694 a or in the reservoir to determine the pressure of the conductivefluid 612 a. The PVDF film sensor may be affixed to the contact head 695a. The PVDF film sensor may be used to measure contact with an object ofinterest or vibrations of the object, such as when the object is movingtangentially to the contact head 695 a. The PVDF film sensor may also beused as a shear sensor to detect movement of the object tangential tothe contact head 695 a. A common contact surface may be a continuoussheet shared by a plurality of sensor cells 600 a. For example, thecommon contact surface may comprise a skin covering the plurality ofsensor cells 600 a to prevent contaminants from entering between cells600 a. Accordingly, a PVDF film sensor, such as a shear sensor, may be asmall portion of the overall contact area of the contact surface.

The touch sensor 600 a may be controlled by a processor (not shown)and/or computer software stored in a memory (not shown). The processormay also be coupled to an output device (not shown), such as a digitalread out, monitor, speaker, printer, or the like, and an input device(not shown), such as a mouse, keyboard, touch screen, microphone, or thelike, to allow an operator to control the touch sensor 600 a.Alternatively, the computer software may be configured to autonomouslycontrol movement of the touch sensor 600 a. The processor may control apump (not shown) to add or remove fluid 612 a to the extension and/orretraction chambers 692 a, 694 a. The pump may be a positivedisplacement pump configured to trap a fixed volume of fluid anddischarging the fixed volume from an outlet. The positive displacementpump may allow the piston 690 a to be moved in fixed and/or measurableincrements. The pump may comprise plastic and/or a non-conductivematerial to insulate the pump from the conductive fluid 612 a.

FIG. 6C is a cross-section view of a touch sensor 600 b comprising abladder 618 b and a piston assembly. Like the touch sensor 600 a withouta bladder, the touch sensor 600 b may include stationary and movableelectrodes 620 b, 630 b; extension and retraction chambers 692 b, 694 b;a piston rod 691 b, a piston head 690 b, and a contact head 695 b;conductive fluid 612 b; and cell walls 616 b. The cell walls 616 b maydefine a cylinder-shaped cavity. Wires (not shown) may be insertinjection molded into the cell walls 616 b, the piston head 690 b,and/or the piston rod 691 b.

A bladder 618 b may enclose the extension chamber 692 b to prevent theconductive fluid 612 b from leaking. The retraction chamber 694 b maycontain a gas and not a liquid. In an embodiment, the extension and/orretraction chambers 692 b, 694 b may each include a bladder 618 b and/orbellows. Alternatively, a single bladder and/or bellows may enclose theextension and retraction chambers 692 b, 694 b and may be attached toboth sides of the piston 690 b. Smaller sensor cells may be particularlyprone to leaking if bladders and/or bellows are not included. Thebladder 618 b and/or bellows may be an insulating sleeve to insulatecell walls 616 b from the conductive fluid 612 b. The bladder 618 band/or bellows may comprise surgical rubber. The bladder 618 b and/orbellows may be configured to fold inside itself and around the piston690 b and/or to roll up as it is compressed. The bladder 618 b maycompletely seal the fluid 612 b without the use of O-rings and mayeliminate the possibility of leaking under normal circumstances.

There are many ways to move the movable electrode relative to thestationary electrode while changing the volume of electrically operativefluid separating them. Sensor cells 610 a with pistons and sensor cells110 without pistons are exemplary embodiments that are not intended tobe restrictive. Variations on these embodiments and/or embodiments thathave not been explicitly are also contemplated. For example, astationary electrode may be affixed to a piston, and a movable electrodemay be affixed to a housing configured to interact with an object.

Sensor Array Comprising Parallel and Series Sensor Cells

FIG. 7 is a side view of a touch sensor 700 comprising a plurality oflayers of sensor cells 710, 720, 730, 740 arranged in parallel andseries with one another. Some of the illustrated layers of sensor cells710, 720, 730 comprise pistons (not shown) and operate in the manner ofsensor cell 610 a. Other layers of sensor cells 740 may comprise anarray of sensor cells with flexible walls, such as sensor cell 110 and200. In alternate embodiments, only sensor cells 110, only sensor cells610, or a different combination of the two may be used instead. A firstsensor cell 710 is disposed at the proximal end of the sensor 700 and isthe largest of the plurality of sensor cells 710, 720, 730, 740. In theillustrated embodiment, the largest sensor is 1 inch by 1 inch. In otherembodiments, it may be larger or smaller based on the particularapplication. A plurality of medium sized sensor cells 720 may be inseries with the largest sensor cell 710; a plurality of small sizedsensor cells 730 may be in series with the medium sensor cells 720; anda plurality of the final layer of contact sensor cells 740 may be inseries with the small sensor cells 730. The final layer of contactsensor cells 740 may be configured to grasp, contact, and/or interactwith an object. The final, small, and medium sensor cells 740, 730, 720may be disposed on the contact heads of the small sensor cells 730,medium sensor cells 720, and largest sensor cell 710 respectively. Oneof the sensor cells 740 in the final layer may be considered to bemechanically in series with any sensors cells 710, 720, 730 in previouslayers that can adjust the position of the one in the final layer.Sensor cells 710, 720, 730, 740 may be considered to be mechanically inparallel if neither one's movement affects the other's position and/orif the sensor cells 710, 720, 730, 740 are in the same layer.

In the illustrated embodiment, there are nine small sensor cells 730 permedium sensor cell 720 and nine medium sensor cells 720 per large sensorcell 710, which gives a nine-to-one ratio of sensor cells betweenlevels. As a result, the medium sensor cells 720 may be approximately0.3 inches by 0.3 inches and the small sensor cells 730 may beapproximately 0.1 inches by 0.1 inches. In other embodiments, the ratiomay be larger or smaller than nine-to-one, or the large-to-medium ratiomay not be the same as the medium-to-small ratio. The final sensor cells740 may have a one-to-one ratio with the small sensor cells 730. Inother embodiments, this ratio may be larger or smaller. As can be seenin the illustrated embodiment, ratios of sensor cells from one layer tothe next may vary across layers. Alternatively, the ratio may beconstant across all layers. Although four layers of sensor cells 710,720, 730, 740 in series are illustrated, a greater or fewer number oflayers in series may be used in other embodiments. There are also manypossible shapes for the contact heads 715, 725, 735, 745 of the sensorcells such as square, circular, triangular, hexagonal, or the like. Bystacking the piston sensor cells 710, 720, 730, a travel length of thepiston in each sensor cell 710, 720, 730 can be reduced. For example,the largest sensor cell 710 may have a travel length of 0.5 inches, themedium sensor cells 720 may each have a travel length of 0.25 inches,and the smallest sensor cells 730 may each have a travel length of 0.125inches. This allows for a total travel length of 0.875 inches withoutrequiring a large travel length for the smallest sensors 730. In theillustrated embodiment, the total length of the three layers 710, 720,730 is 2 inches.

The large number of sensor cells 710, 720, 730, 740 can result in asignificant number of wires (not shown) for measurement and control ofeach sensor cell and a significant number of electrical propertymeasuring devices (not shown). The number of wires and electricalproperty measuring devices may be reduced by multiplexing together thesignals on the wires from the sensor cells 710, 720, 730, 740. Thesignals may be time division multiplexed in a fixed order, or aprocessor may control the multiplexing. The multiplexing may beperformed using integrated circuits or by mechanical means. Forintegrated circuits, chips may be placed on the bases 718, 728, 738 ofeach layer of the piston sensor cells 710, 720, 730. The final layer ofcontact sensor cells 740 may include an integrated circuit inside thecontact sensor cells 740 for multiplexing. In some embodiments, onlysome layers or sensor cells 710, 720, 730, 740 are multiplexed. One ormore amplifiers may be used before or after the multiplexers to creategreater precision and to mitigate noise. Amplifiers may also benecessary for low resistance conductive fluids, such as gallium alloys.Additionally, one or more analog-to-digital converters (ADC) may be usedbefore or after multiplexing the signals from measurement wires tosample and quantize the signals. Analog or digital demultiplexing may beused in various embodiments to separate the signals. The touch sensor700 may be a modular design that can be stacked in length and/or height.The touch sensor 700 may be affixed into gripper jaws or fingers in anyconfiguration to enable a flexible design to grasp various sized andshaped objects. The touch sensor 700 may be designed with a singleflexible skin on the final sensor layer 740. A plurality of touch sensor700 may be stacked as complete units with each module having a separateskin covering the final sensor layer 740. The touch sensor 700 may bedesigned with thin walls and may be closely stacked to preventcontaminants from entering between the modules and to reduce the areathat is not measuring the object geography. The total thicknessseparating individual cells may be 0.020 inches or less including thewalls.

FIGS. 8A and 8B are side views of a touch sensitive gripping systems 800a and 800 b comprising a plurality of opposing touch sensor arrays. Thetouch sensitive gripping arrays 800 a and 800 b may be used to grasp anobject 860. Like the touch sensor array 700, each touch sensor array810, 820, 830, 840, 850 may comprise a first layer 811, 821, 831, 841,851; a second layer 812, 822, 832, 842, 852; a third layer 813, 823,833, 843, 853; and a fourth layer 814, 824, 834, 844, 854. A finalcontact layer (not shown) may also be added in some embodiments. Thefinal contacts in each touch sensor array 810, 820, 830, 840, 850 mayall be physically connected together by a single insulating wall and/orskin, or the final contacts may be separated into sections correspondingto the cross sectional area of any of the first layer 811, 821, 831,841, 851, the second layer 812, 822, 832, 842, 852, the third layer 813,823, 833, 843, 853, the fourth layer 814, 824, 834, 844, 854, or thefinal layer. The insulating wall and/or skin may comprise silicon rubberor the like. The single insulating wall and/or skin may increase thestability of the extended pistons and/or keep contaminants from enteringbetween the sensor cells.

In some touch sensor arrays 810, 820, 850, the first layer 811, 821, 851may comprise a plurality of sensor cells. In the illustrated embodiment,the first and second touch sensor arrays 810, 820 and the fourth andfifth touch sensor arrays 840, 850 directly oppose one another. Thethird touch sensor array 830 may be at a right angle to the first andsecond sensor arrays 810, 820. The fourth and fifth sensor arrays 840,850 may be at right angles to the first and second sensors arrays 810,820, as well as the third sensor array 830. The sensor arrays 810, 820,830 in the gripping array 800 a may lie in a two-dimensional plane. Inthe gripping array 800 b, five sensor arrays 810, 820, 830, 840, 850 mayoccupy a three-dimensional space. In other embodiments, there may be agreater of fewer numbers of sensor arrays 810, 820, 830, 840, 850 inone, two, or three dimensions. For example, there may be two, four, orsix touch sensor arrays and/or modules at right angles to each otherand/or opposing each other. The touch sensor arrays 810, 820, 830, 840,850 may also be at 60 degree angles from one another and form atriangular shape. The illustrated embodiment is configured to graspobjects from the outside, but other embodiments may be configured tograsp an object from inside.

FIG. 9 is a flow diagram of a method 900 for calibrating a touchsensitive gripping system 800 a and grasping an object 860. A similarmethod may be used for gripping system 800 b. Before grasping the object860, the touch sensitive gripping system 800 a may be calibrated byfully retracting 902 the pistons (not shown) in each sensor cell to aminimum extension position. The minimum extension position maycorrespond with a mechanical stop, a fill limit for the reservoir, fullextension or retraction of the pistons, and/or the electrodes touching.Next, the pistons in the sensor cells in each layer 811, 812, 813, 821,822, 823, 831, 832, 833 may be extended 904 until the contact surfaces815, 825, 835 of the sensor arrays 810, 820, 830 are touching eachother. This is the maximum extension position for the sensor arrays 810,820, 830, which may be regulated by contact pressure. In someembodiments, extension may precede retraction. The touch sensor 800 amay be calibrated by mapping 906 the measured minimum and maximumextension positions to displacement. The calibration may comprisedetermining a measured electrical property to displacement curve, suchas a voltage to distance curve. A voltage to distance curve and/or adigital calibration of voltage to distance may be created for eachsensor in the sensor arrays 810, 820, 830, 840, 850. In someembodiments, the displacement between the maximum and minimum extensionpositions can be measured and input to a processor (not shown) to definephysical measurement units for a displacement being measured. In otherembodiments, the displacement being measured may be expressed as afraction or percentage of the displacement between the minimum andmaximum extension positions. Displacements may be expressed relative tothe maximum extension position and/or relative to the minimum extensionposition.

Once the gripping system 800 a is calibrated, it may be used to graspthe object 860. The sensor cells in every layer 811, 812, 813, 821, 822,823, 831, 832, 833 of the sensor arrays 810, 820, 830 may start by beingretracted 908 to the minimum extension position. Each piston in thefirst layer 811, 821, 831 may be extended 910 until the object 860 iscontacted by a contact surface 815, 825, 835 in series with each pistonin the first layer 811, 821, 831, or each piston reaches the maximumextension position. In some embodiments, each piston may continue toextend after initial contact until a predetermined maximum pressure ismeasured by a pressure sensor for each sensor cell 811, 821, 831. Inother embodiments, only the sensor cells in one layer may have pressuresensors, and the pistons may be extended until a pressure sensor in asensor cell in series with the piston reaches a predetermined threshold.Multiple sensor cells may also be connected to a single pressureregulator and/or hydraulic pump, and extension may be limited by thein-line pressure detected by the regulator and/or pump. The pressure maybe regulated to the cells, individually or collectively, by one or morehydraulic valves.

Once every piston in the first layer 811, 821, 831 has extended untilcontact with the object 860 has been made with sufficient pressure, orevery piston has reached the maximum extension point, the grippingsystem 800 a may begin extending 912 the pistons in the second layer812, 822, 832. Again, every piston may be extended until the object 860is contacted with sufficient pressure by a contact surface 815, 825, 835in series with each piston in the second layer 812, 822, 832 or untilthe pistons reach their maximum extension point.

The third layer 813, 823, 833 may be extended 914 until a contactsurface in series with every piston in the third layer 813, 823, 833makes contact with sufficient pressure or reaches its maximum extensionpoint. In those embodiments where the processor controls multiplexing,the processor may speed operation by only multiplexing measurement andcontrol of sensor cells that have not yet made contact with the object860 with sufficient pressure. In some embodiments, the pistons may allbe pressure regulated by the same pumping and reservoir system usingsingle or multiple control valves to control selected piston pressure sothat simultaneous extension results until sufficient contact pressure isindicated by a pressure feedback loop. Pressure feedback may be receivedfrom piezoresistive sensors (not shown) in the back of the contactsurfaces 815, 825, 835. In certain embodiments, one pump may be used perseries array. Thus, multiple layers 811, 812, 813, 821, 822, 823, 831,832, 833 may be extended simultaneously in some embodiments.

Once each piston has finished being extended, the processor maycalculate 916 the position of each contact point with the object 860.This can be done by taking the displacement the flexible wall has movedin the fourth layer 814, 824, 834 and adding the displacements travelledby each piston in the third layer 813, 823, 833; the second layer 812,822, 832; and the first layer 811, 821, 831 in series with that piston.The plurality of total displacements calculated may be used to generatea geographic model of the object 860 and/or to determine the object'sspecific location and orientation in the gripping system 800 a. Thegeographic model may include a differential volume and/or perimeterdetermined from the movement of the sensor cells relative to thecalibrated reference points. A predetermined area of each sensor cellmay be multiplied by the displacement travelled by the sensor cell todetermine a corresponding volume. A plurality of volumes may be summedto determine a total volume, and/or the geographic model may beassembled from volumes determined for each sensor cell. The object 860can be manipulated based on the geographic model generated and thelocation determined. For additional objects, the gripping system 800 amay be recalibrated using steps 902, 904, and 906, or the grippingsystem 800 a can jump to step 908 and skip calibration.

Sensor Array with Sensors not Separated by Insulating Walls

FIG. 10 is a cross-section view of a sensor array 1000 comprising aplurality of electrodes 1020 a-d, 1030 a-d not separated by insulatingwalls. A single sensing chamber 1018 containing a conductive fluidcomprises all the electrodes 1020 a-d, 1030 a-d allowing electricalenergy to conduct between any stationary electrode 1020 a-d and anymovable electrode 1030 a-d. Like sensing cell 110, the movableelectrodes 1030 a-d may be embedded in a flexible substrate 1014. Themovable electrodes 1030 a-d then move as the flexible substrate 1014 ispressed against an object to grip that object. The flexible substrate1014 may comprise latex, plastics, natural and/or synthetic rubbers,and/or silicones. The connections to the movable electrodes 1030 a-d mayalso be embedded in the flexible substrate 1014 to prevent theirexposure to the conductive fluid. In some embodiments, the electrodes1020 a-d, 1030 a-d may comprise conductive ink. The conductive ink maybe printed with an inkjet printer or the like onto the flexiblesubstrate 1014. The conductive ink may be coated with silver, silverchloride, tungsten, or tantalum using vapor deposition, chemicaldeposition, etching, electrolysis, dipping, or the like. The depositedmaterial may prevent the conductive ink from being in contact with theconductive fluid thus protecting the conductive ink from corrosiveconductive fluids. In some embodiments, the stationary electrodes 1020a-d may be replaced with a single, large electrode that interacts withall of the movable electrodes 1030 a-d. The stationary electrodes 1020a-d may be connected to a multiplexer (not shown) to cycle through eachof the electrodes 1020 a-d. The movable electrodes 1030 a-d may beconnected to the same multiplexer and/or a separate multiplexer. Aprocessor may switch through the electrode pairs 1020 a, 1030 a; 1020 b,1030 b; 1020 c, 1030 c; 1020 d, 1030 d in sequence to create a closedcircuit through each pair. In an embodiment with two multiplexers, themultiplexers may cycle together and/or a common select signal may besent to both multiplexers to ensure that opposing pairs of electrodes1020 a-d, 1030 a-d are activated, or the stationary electrode may be asingle electrode in common to all the movable electrodes 1030 a-d.

FIG. 11 is an overhead view of a sensor array 1100 without internal,insulating walls. The sensor array 1100 comprises 16 individual sensingelements 1110 in a two-dimensional array. Each sensing element 1110 maycomprise a piston (not shown) with a movable electrode (not shown) onit, or the movable electrodes may be affixed directly to a flexiblesubstrate 1114. Thus, a sensor array without internal, insulating wallsmay be implemented either with flexible walls like sensor array 200 orwith pistons like the layers of sensors 710, 720, 730. In someembodiments of touch sensors 700, the final layer 740 may comprise asensor array 1100 without insulating walls. Similarly, the fourth layers814, 824, 834, 844, 854 in touch sensitive gripping systems 800 a and800 b may be implemented by sensor arrays 1100 without insulating walls.The flexible substrate 1114 may be made of latex; plastics; natural andsynthetic rubbers, such as silicon rubber; silicones; and the like.

FIG. 12A is a bottom view of a flexible substrate 1214 a for a sensorarray 1200 a without internal, insulating walls. The flexible substrate1214 a may include a plurality of contact points 1211 a (also referredto herein as “lands”). The contact points 1211 a may include aconductive material, such as conductive ink, which may be inkjet printedonto the flexible substrate 1214 a. A plurality of wires 1212 a mayprovide external connections to electrodes 1230 a. The plurality ofwires 1212 a may also be inkjet printed onto the substrate 1214 a. Inthe illustrated embodiment, the plurality of wires 1212 a may all exitthe inside of the sensor array 1200 a on the same side. The plurality ofwires 1212 a may be covered with an insulator such that only the contactpoints 1211 a remain exposed. The movable electrodes 1230 a may then beattached to the contact points 1211 a.

FIG. 12B is a front perspective view of an alternate embodiment of asensor array 1200 b without internal insulating walls. In an embodiment,the dimensions of the sensor array 1200 b are 0.25 inches by 0.25 inchesby 0.25 inches. Unlike the sensor array 1200 a, the plurality of wires1212 b may exit the inside of the sensor array 1200 b on a plurality ofdifferent sides. A plurality of contact points 1211 b and the pluralityof wires 1212 b may be inkjet printed onto a flexible substrate 1214 b.The flexible substrate 1214 b may comprise silicon. An additionalsubstrate layer 1215 b may cover the wires 1212 b and leave only thecontact points 1211 b exposed. Movable electrodes 1230 b may be attachedto the exposed contact points 1211 b. In an embodiment, the movableelectrodes 1230 b may be inkjet printed onto the exposed contact points1211 b.

The flexible substrate 1214 b and additional substrate layer 1215 b maybe attached to a sensor array body 1240 b. The flexible substrate 1214b, additional substrate layer 1215 b, and the sensor array body mayinclude external wires 1244 b along the outside edges. The externalwires 1244 b may be inkjet printed onto the exteriors of the flexiblesubstrate 1214 b, additional substrate layer 1215 b, and sensor arraybody 1240 b before and/or after the flexible substrate 1214 b,additional substrate layer 1215 b, and sensor array body 1240 b havebeen attached to one another. The external wires 1244 b may be coupledto a multiplexer (not shown) and may be coated in an insulatingmaterial. The insulating material may be hard polytetrafluoroethylene(e.g., Teflon®), such as is produced by Chem Processing Inc. or AmericanDurafilm. Alternatively, or in addition, the plurality of wires 1212 band/or the external wires 1244 b may be flexible flat wire/cable and maybe attached to the flexible substrate 1214 b, additional substrate layer1215 b, and/or sensor array body 1240 b. Flexible flat wire/cable may beavailable from Z-Axis Connector Company, DIY Trade, or MouserElectronics.

A fill hole 1242 b may allow a conductive or dielectric fluid to beadded to the sensor array 1200 b after it has been sealed. A fill hose(not shown) may be coupled to the fill hole 1242 b to add the fluid. Thesensor array 1200 b may be spun in a centrifuge with the fill hose stillattached to remove air bubbles though the fill hose. Once any airbubbles have been removed, the fill hole 1242 b may be sealed.

FIG. 13 is a cross-section view of a sensor array 1300. In theillustrated embodiment, the sensor array 1300 includes 16 movableelectrodes 1330 and 16 stationary electrodes 1320. Alternatively, moreor fewer electrodes 1320, 1330 may be included in other embodiments,and/or the movable electrodes 1320 may be a single electrode of areaequal to or less than the sum of the areas of the 16 stationaryelectrodes 1330. The electrodes 1320, 1330 may include a conductivematerial, such as silver, conductive ink, any previously discussedconductive material, or the like. The movable electrodes 1330 may beinkjet printed and/or attached to a flexible substrate (not shown) asdiscussed above. The stationary electrodes 1320 may be attached to astationary electrode housing 1325. The stationary electrode housing 1325may be made of a high Young's Modulus non-conductive material, such ascarbon-fiber-reinforced plastic. The flexible substrate and/orstationary electrode housing 1325 may be electrically and/ormechanically coupled to one or more sidewalls 1340. The one or moresidewalls 1340 may include one or more printed circuit boards (PCBs)1341, such as single-sided and/or double-sided PCBs. The sidewalls 1340may be made of a flexible material, such as flat wire/cable, siliconrubber, flexible PCB, or the like. On contact pressure with an object,the sidewalls 1340 may flex and allow the movable electrodes 1330 tomove close to the stationary electrodes 1320. In an embodiment, twoopposing sidewalls 1340 may include PCBs 1341, silicon rubber withembedded wires, and/or flexible cable, and another two sidewalls 1340may not include PCBs 1341, wires, and/or flexible cables. Othersidewalls enclosing the sensor array 1300 may also be flexible. The oneor more sidewalls 1340 may electrically couple the stationary and/ormovable electrodes 1320, 1330 to a base plate 1350. The base plate 1350may include a double-sided PCB configured to electrically couple thestationary and/or movable electrodes 1320, 1330 to a multiplexer 1360.The base plate 1350 may include through holes and/or vias to couple theelectrodes 1320, 1330 to the multiplexer 1360. The multiplexer 1360 maybe electrically coupled with measuring and/or processing components (notshown) as discussed above.

The sensor array 1300 may be filled with an electrically operative fluid(not shown). The stationary electrode housing 1325 may include offsets1326 that support the stationary electrode housing 1325. The offsets1326 may space the stationary electrode housing 1325 from the walls 1340to create a baffle and allow fluid to flow around the stationaryelectrode housing 1325. A bladder 1318 may be included to preventleaking of the electrically operative fluid. The bladder 1318 may bedesigned with a lower Young's Modulus than the sidewalls 1340. In anembodiment, the sidewalls 1340 may include silicon rubber with a greaterthickness, and the bladder 1318 may include silicon rubber of a lesserthickness. The bladder 1318 may be configured to allow expansion of thebladder as the fluid is displaced so that the sidewalls 1340 do notbulge. The sidewalls 1340 may include a material with a Young's Modulushigher than the bladder 1318 and/or a material thicker than the bladder1318 with the same Young's Modulus as the bladder to prevent deformationof the sidewalls. The offsets 1326 and bladder 1318 may permitdisplacement of the electrically operative fluid so that the flexiblesubstrate can conform to an object (not shown). The thickness and/orelastic modulus of the bladder 1318 may be selected to allow sufficientdisplacement for the flexible substrate to conform to the shape of theobject. A similar substance may be included in both the flexiblesubstrate and the bladder 1318, e.g. silicon rubber. The bladder 1318and flexible substrate may be a similar size and thickness in someembodiments. Alternatively, a bladder 1318 thinner than the flexiblesubstrate may reduce side bulging of the flexible substrate.

The sensor array 1300 may also include a shear sensor 1371, a pressuresensor 1372, and a temperature sensor (not shown). The shear sensor 1371may be in contact with the flexible substrate and/or movable electrodes1330 and detect shear force on the opposite side of the flexiblesubstrate. The shear sensor 1371 may be perpendicular to the electrodes1330 and/or parallel to the one or more sidewalls 1340. In someembodiments, more than one shear sensor 1371 may be used to detect shearforce in multiple directions and/or locations. The shear sensor 1371 maybe a PVDF film sensor, a piezoresistive sensor, or the like. Thepressure sensor 1372 may be in contact with the bladder 1318 and/or theelectrically operative fluid. A probe for the temperature sensor may beattached to the one or more sidewalls 1340, in hydraulic fluid lines(not shown), in contact with the flexible substrate, in contact with theobject, in contact with the bladder 1318, in contact with the stationaryand/or movable electrodes 1320, 1330, and/or in contact with theelectrically operative fluid. Electrical lead wires (not shown) maycouple the shear sensor 1371, pressure sensor 1372, and/or temperaturesensor to the one or more sidewalls 1340. The one or more sidewalls 1340and/or the multiplexer 1360 may transmit sensor measurements to theprocessor.

Insert injection molding may be used to form the walls 1340. The walls1340 may encompass flexible cables and/or inkjet printed electricalwires, the base plate 1350, and the offsets 1326 and may circumscribethe sensors 1371, 1372, the electrodes 1320, 1330, and the bladder. Theoffsets 1326 may be attached to the flexible cables, and/or the offsets1326 may be insert injection molded into the sidewalls 1340. In anembodiment, the walls 1340, base plate 1350, bladder 1318, PCBs 1341,stationary electrode housing 1325, and the flexible substrate arecoupled to each other by silicon rubber. The offsets 1326, the bladderand bladder housing 1318, and the PCBs 1341 add support to the sidewalls1340. The electrical lead wires to the shear sensor 1371, pressuresensor 1372, temperature sensor, movable and/or stationary electrodes1320, 1330, and the like may be covered by a moldable plastic, such as athermoplastic, during the injection molding. The moldable plastic mayelectrically insulate any electrical connections other than theelectrodes 1320, 1330 from coming into contact with the electricallyoperative fluid.

FIG. 14 is a schematic diagram of a sensor 1400 comprising controlcircuitry and a sensor array without internal, insulating walls. Thecontrol circuitry may control power to the electrode pairs 1410 a-d toallow for accurate measurement. Each electrode pair 1410 a-d may becontrolled by a switch 1420 a-d that determines whether or not powerfrom a power source 1440 flows to that electrode pair 1410 a-d. Theswitches 1420 a-d may be implemented as field effect transistors madefrom silicon, gallium arsenide, carbon nanotubes, or the like. A fieldeffect transistor may have its source connected to the power source 1440and its drain coupled to one of the electrode pairs 1410 a-d. Theswitches 1420 a-d may be embedded in or on the flexible substrate or maybe located away from the electrode pairs 1410 a-d. For example, a fieldeffect transistor made from carbon nanotubes may be particularlyresistant to damage from flexing of the flexible substrate. Thin filmmetal may be used to electrically couple the switches 1420 a-d with theelectrode pairs 1410 a-d.

In some embodiments, the switches 1420 a-d may only allow one pair ofelectrodes 1410 a-d to be powered at a time, such as only directlyopposing electrodes. In the illustrated embodiment, each movableelectrode (not shown) is paired with a stationary electrode (not shown)opposite to it. A processing unit or the like may cycle which switch1420 a-d is enabled until the displacement between every electrode pair1410 a-d has been measured. Internal impedances of the circuitry maycontrol the maximum sampling rate that still allows for accuratemeasurements. In some embodiments, the switches 1420 a-d may be coupledwith the movable electrodes. In other embodiments, the switches 1420 a-dmay be coupled with the stationary electrodes. Some embodiments may haveswitches 1420 a-d for both the stationary and movable electrodes.Non-opposing electrodes may be enabled to measure shear force on thegripping surface (not shown). The circuit may comprise one or moremultiplexers (not shown) to consolidate signals to a single measuringdevice (not shown) or there may be a measuring device for each electrodepair 1410 a-d. Signals may also be amplified and filtered before orafter multiplexing. Consolidated signals may be demultiplexed beforesampling and relay to a processing unit or the processing unit may beprogrammed to properly interpret multiplexed signals.

FIG. 15 is a schematic diagram of a sensor 1500 comprising a controlmultiplexer 1520 and a sensor array without internal, insulating walls.The multiplexer 1520 may allow power to be supplied to only a selectedelectrode pair 1510 a-d. In the illustrated embodiment, the stationaryelectrodes (not shown) are electrically coupled with each other.Alternatively or additionally, the movable electrodes (not shown) mayalso be coupled with each other. In other embodiments, a singlestationary electrode may interact with all of the movable electrodes, orthe stationary electrodes and movable electrodes may not be coupled toeach other. A first multiplexer (not shown) may be connected to thestationary electrodes, and a second multiplexer (not shown) may beconnected to the movable electrodes. Alternatively, a single multiplexermay switch through the pairs of stationary and movable electrodes. Acurrent shunt 1530 may allow a voltage relative to ground to be measuredby a processing unit 1550. In other embodiments, a Wheatstone bridge maybe used to measure resistance rather than the current shunt 1530.

In the illustrated embodiment, the processing unit 1550 controls themultiplexer 1520. In some embodiments, the processing unit 1550 maycomprise a microprocessor (not shown) and an integrated circuit, such asan FPGA, ASIC, or the like (not shown). The multiplexer 1520 may beimplemented in the integrated circuit or may be an off the shelf ASICcontrolled by the integrated circuit. The integrated circuit may alsocomprise an ADC to measure the voltage across the current shunt 1530.The integrated circuit may also be able to efficiently handle parallelcomputations to convert voltage measurements to displacements beforeoutputting the displacements to the microprocessor with a high bandwidthlink. This may allow the integrated circuit to manage the controlcircuitry and perform lower level calculations, while the processor usesthe preprocessed data received from the integrated circuit to performhigher level modeling. Carbon nanotube integrated circuits embedded intothe flexible substrate may comprise all or part of the switches,electrodes, microprocessor, multiplexer, and/or demultiplexer.Microfluidic channels may be used for electrodes with very small contactareas to enhance electrical coupling between the conductive fluid andthe stationary and movable electrodes.

Determining Relative Permittivity and/or Resistivity of an Object

A gripping system may be used to measure a capacitance across an objectbeing gripped. Because the distance between the capacitor plates isknown, a relative permittivity of the object may be determined from thecapacitance. In some embodiments, determining the relative permittivitymay comprise computing a dielectric constant for the object.Alternatively or additionally, a resistance of the object being grippedmay be measured. Measurements of the length of the object and the areaof the object from the gripping system may be used with the measuredresistance to determine a resistivity of the object. In someembodiments, the relative permittivity may be determined for insulators,the resistivity may be determined for conductors, and the relativepermittivity and/or resistivity may be determined for semiconductors.

The relative permittivity and/or resistivity may be used to identify thecomposition of an object by comparing the determined/measured value toknown values for various materials or to previously measured values forvarious objects. Once the material of the object is known, properties ofthe object or the weight of the object may be predicted from thematerial. The relative permittivity and/or resistivity may also be usedto determine the purity of an object or the existence of hazardousmaterials on the object. These determinations may be beneficial in thesemiconductor industry and the like. The additional data from measuringthe relative permittivity and/or resistivity may allow for betterprocess control, increased efficiency, and superior products.

FIG. 16A is a schematic diagram of a relative permittivity sensor 1600 acomprising opposing sensor cells 1611 a, 1612 a. The opposing sensorcells 1611 a, 1612 a may comprise pistons and/or flexible walls. In theillustrated embodiment, the movable electrodes 1631, 1632 may be used asplates of a capacitor with an object 1660 acting as the dielectric forthe capacitor. In other embodiments, the fixed electrodes 1621, 1622 orboth the fixed and movable electrodes 1621, 1622, 1631, 1632 may be usedas the plates of the capacitor. A separate voltage line may be suppliedto the movable electrodes 1631, 1632, or one or more switches may beused to change between displacement measuring and capacitance measuring.

In some embodiments, displacement measuring may not be performed duringcapacitance measuring, and the fixed electrodes 1621, 1622 may be at thesame voltage as the movable electrodes 1631, 1632 or allowed to float.Correspondingly, opposing movable electrodes 1631, 1632 may be at thesame voltage, one may be allowed to float during displacementmeasurement, and/or the opposing electrodes 1631, 1632 are not energizedat the same time during displacement measurement to prevent capacitiveinterference. In embodiments, the object 1660 may be ejected by applyinga voltage of the same polarity to both movable electrodes 1631, 1632 ormay be attracted in between the electrodes 1631, 1632 when a voltage isapplied across the electrodes 1631, 1632. This may be used to grab orrelease an object, such as when using micromachinery.

In some embodiments, the sensor 1600 a may use only one pair of directlyopposing electrodes. Alternatively, a predetermined plurality ofelectrodes and/or non-directly opposing electrodes may be used. Forexample, measuring permittivity of hollow objects with directly opposingelectrodes may require an excessively large voltage, so electrodesangled relative to one another may be selected in such instances.Alternatively, the shape of the object 1660 may cause the movableelectrodes 1631, 1632 to be angled rather than directly opposing oneanother. The angles may be between 0 degrees and 180 degrees in someembodiments and between −180 degrees and 180 degrees in others. Forangled plates, the electric field may arch through the object 1660. Thearching of the electric field may depend on the thickness and materialof the object 1660. The voltage may be increased until the electricfield extends out of the object 1660. When the permittivity is detectedto be that of air and/or there is a change in permittivity from that ofthe object 1660, an edge of the object 1660 may be indicated. Inalternate embodiments, edge detection may be performed by changing oneplate of the capacitor to a different sensor cell's movable electrodeuntil the permittivity of air is detected.

Detecting changes in the permittivity of an object 1660 can be used todetermine a thickness of an object wall. Various capacitor platearrangements may be used to detect changes in permittivity. Thecapacitor plates may be arranged in close proximity, such as a seriescapacitor plate alignment, to cause the electric field to form an archbetween the capacitor plates. A measured capacitance of the archingfield may depend on the permittivity of each material through which thefield passes, such as an object wall and a material behind the objectwall like water or air. For example, a small electric field applied to aglass of water by series plate capacitors may first penetrate throughthe glass. As the electric field is increased, the electric field maypenetrate through the water and the glass. A change in capacitance asthe electric field is increased may indicate the electric field ispassing through a material with a different permittivity value.

The electric field between capacitor plates may create an arch with theseries plate alignment. Increasing the voltage from a low value to ahigh value across the capacitor may cause the electric field to projectfrom one layer of the object to another layer of different material asthe arching electric field is increased. The capacitor voltage may alsobe monitored in order to determine changes in materials. Changes in theshape of the voltage curve may also be used to indicate the thickness ofthe different layers of object materials. The change in dielectricconstant of the various materials of the object may cause ripples in thevoltage-time curve as a function of increasing voltage. Comparing thesechanges to stored values may be used to determine the wall thickness ofan object.

The voltage across a capacitor may be expressed using the equation:

$\begin{matrix}{V = {{\frac{1}{C}{\int_{0}^{t}{{i(\tau)}{\tau}}}} + {V(0)}}} & (1)\end{matrix}$

wherein V is the voltage across the capacitor at time t, V(0) is thevoltage across the capacitor at time 0, C is the capacitance value ofthe capacitor, and i(τ) is the current into and out of the capacitor.The impedance of the capacitor may be expressed as:

$\begin{matrix}{Z = {\frac{1}{{j\omega}\; C} = {- \frac{j}{2\pi \; {fC}}}}} & (2)\end{matrix}$

wherein Z is the impedance of the capacitor, ĵ2=−1, ω is the angularfrequency, f is the ordinary frequency, and C is the capacitance valueof the capacitor. The capacitor voltage, current, and/or impedance maybe used to detect changes in the dielectric constant as the voltageand/or frequency is increased to project through the different layers ofthe object. Monitoring the shape of the voltage curve may predict thewall thickness and materials of the object. Different voltage and/orfrequency curves may be stored in the processor for comparison to themeasured curve.

The permittivity values for various substances, including substanceswith multiple layers of different materials, may be stored forcomparison with measured values using a processor. A combined equivalentpermittivity value may be computed from the measured capacitance. Thecombined equivalent permittivity value may be dependent on thepermittivity values of each material through which the electric fieldpasses. Alternatively or in addition, the processor may calculate apermittivity profile by comparing a change in applied voltage and/orfrequency relative to a change in capacitance. The combined equivalentpermittivity and/or permittivity profile may then be compared to thestored permittivity values and/or stored permittivity profiles todetermine the thickness of the object wall and/or to determine thematerials of which the object 1660 is comprised. Determining thethickness of the object wall may be important for regulating pressure.The pressure exerted on an object 1660 by a gripper may be controlledthrough feedback of various information. The feedback may include theobject's material, the wall thickness, change in voltage, change inimpedance, change in frequency, and/or the change in permittivity as theelectric field projects through a wall and encounters another material.

A power source 1640 a and measuring device 1650 a may be used to measurethe capacitance, capacitor impedance, and/or capacitor voltage acrossthe object 1660. In some embodiments, the power source 1640 a andmeasuring device 1650 a may be a single device. In other embodiments,additional electrodes (not shown) may be used to create a plurality ofcapacitor circuits, which may be controlled by multiplexers and/ordemultiplexers (not shown). The capacitance, capacitor impedance, and/orcapacitor voltage may be measured by applying a direct current (DC)voltage and measuring current and/or a charging time; applying aconstant current and measuring a rate of voltage change and/or acharging time; applying an alternating current (AC) and measuring theresulting voltage; applying an AC voltage and measuring the resultingcurrent; applying and varying the frequency of an alternating currentand measuring the capacitor voltage; applying and varying the frequencyof an alternating voltage and measuring the capacitor current; using abridge circuit; or the like. With either a constant voltage AC source orconstant current AC source, the magnitude, the phase, and/or a complexrepresentation of the resulting current or voltage can be measured. Avariable frequency switching power supply may be used to provide DC andAC power at various frequencies, power, and/or voltage. Becauseproperties may vary substantially with frequency, the power source 1640a and measuring device 1650 a may have wide programmable frequencyranges. In some embodiments, several measurements may be averaged toincrease accuracy. The voltage applied in any of the above measurementsystems may be low to avoid exceeding the breakdown voltage of theobject 1660 or generating too much heat in the object 1660, which maymostly be a problem for AC powered measurements.

In some embodiments, a plurality of capacitances across the object maybe measured at a corresponding plurality of frequencies. The frequenciesmay be varied from zero (DC) to 10¹⁵ Hertz or higher in embodiments.This may comprise sweeping from low frequency to high frequency.Similarly, the voltage across the movable electrodes 1631, 1632 may beincreased over a plurality of values during measurements. Themeasurements may also be used to determine the dielectric relaxationand/or dissipation factor of the material. The permittivity of amaterial may also depend on the length of time the material is exposedto an electric field as well as the temperature of the material. Thus,capacitances may be measured for multiple exposure times, and atemperature of the dielectric may be measured.

A relative permittivity of the object may be determined from the one ormore measured capacitances. In some embodiments, the relativepermittivity may be computed using a processor. Because walls, air gaps,and the like are in between the movable electrodes 1631, 1632 and cancontribute to the capacitance measurement, the sensor 1600 a may becalibrated initially to account for the permittivity of these sensorcomponents before determining the relative permittivity of the object.Alternatively, air gaps may be reduced or eliminated by applying aliquid to the robotic gripper. In some embodiments, the liquid maycomprise a polar solvent, such as water. Due to the higher permittivityof water, capacitance measurements may be increased, allowing moreprecise measurements at lower voltages. To calibrate the sensor 1600 a,the sensor cells 1611 a, 1612 a first may be brought together until theyare touching. One or more capacitances of the sensor components may thenbe measured at one or more frequencies.

The relative permittivity of the sensor components may be determinedaccording to the equation:

$\begin{matrix}{C = \frac{ɛ_{sensor}ɛ_{0}A}{d_{sensor}}} & (3)\end{matrix}$

wherein ∈_(sensor) is the relative permittivity of the sensorcomponents, d_(sensor) is the distance between the movable electrodes,∈₀ is the vacuum permittivity, and A is the area of the electrodes 1631,1632. In some embodiments, the vacuum permittivity and electrode areamay be predetermined values, and the value ∈_(sensor)/d_(sensor) foreach frequency may be stored to account for the sensor components. Thepermittivity of sensor components may be determined during step 904 ofthe displacement calibration. In other embodiments, the sensor cells1611 a, 1612 a may be separated by a predetermined displacement duringcomputation of the relative permittivity for sensor components and/or∈_(sensor) may be stored. Equation 3 comprises units from theInternational System of Units (SI). In other embodiments, Gaussian unitsor other unit systems may be used to calculate permittivity. In Gaussianunits, the dielectric constant k may be computed according to theequation:

$\begin{matrix}{C = \frac{k_{sensor}A}{4\pi \; d_{sensor}}} & ( {3a} )\end{matrix}$

The relative permittivity of the object 1660 may then be computed from ameasured capacitance using the equation:

$\begin{matrix}{C = \frac{ɛ_{0}A}{\frac{d_{object}}{ɛ_{object}} + \frac{d_{sensor}}{ɛ_{sensor}}}} & (4)\end{matrix}$

which can be rewritten:

$\begin{matrix}{ɛ_{object} = \frac{d_{object}}{\frac{ɛ_{0}A}{C} - \frac{d_{sensor}}{ɛ_{sensor}}}} & (5)\end{matrix}$

wherein d_(sensor) is the distance between the electrodes attributableto sensor components, ∈_(object) is the relative permittivity of theobject 1660, and d_(object) is the distance between the electrodesattributable to the object. If the sensor cells 1611 a, 1612 a weretouching when computing the relative permittivity of the sensorcomponents, then d_(sensor) in equation (3) may be approximatelyd_(sensor) in equation (5) and ∈_(sensor)/d_(sensor) may be directlyinserted into equation (5). Distance measurements made according to thepreviously discussed methods may be used as the distance d_(object).Because all other values are known, ∈_(object) can then be computed.

The computation of the relative permittivity may also compensate for airgaps between the sensor cells 1611 a, 1612 a. The permittivity of anobject 1660 with air gaps may be computed according to the equations:

$\begin{matrix}{ɛ_{object} = \frac{1}{1 - {( {1 - \frac{C_{air}}{C_{{object} + {air}}}} )\frac{d_{plates}}{d_{object}}}}} & (6)\end{matrix}$

wherein the permittivity of air is assumed to be one, d_(plates) is thedistance between the plates including both the air gap and width of theobject, C_(object+air) is the measured capacitance with the object 1660in place, and C_(air) is the measured capacitance at distance d_(plates)with the object 1660 not in place. If C_(air) is not measured, equation6 can also be computed as:

$\begin{matrix}{ɛ_{object} = \frac{1}{1 - {( {1 - \frac{ɛ_{0}A}{d_{plates}C_{{object} + {air}}}} )\frac{d_{plates}}{d_{object}}}}} & ( {6a} )\end{matrix}$

Equation 6 can then be combined with equation 4 to compute the relativepermittivity while accounting for air gaps and sensor components,yielding the equation:

$\begin{matrix}{ɛ_{object} = \frac{1}{1 - {( {1 - \frac{C_{air}}{C_{{object} + {air}}}} )( {\frac{d_{walls}}{d_{object}} - \frac{d_{sensor}}{d_{object}ɛ_{sensor}}} )}}} & (7)\end{matrix}$

wherein d_(wall) is the distance between the sensor cell 1611 a, 1612 aflexible substrate walls (i.e., the sum of d_(walls) and d_(sensor) isthe total distance between the electrodes 1631, 1632).

A dissipation factor for the object 1660 may also be measured in someembodiments. The dissipation factor may also be corrected for air gapsand sensor components. For a measurement with air gaps, the dissipationfactor can be computed according to the equation:

$\begin{matrix}{D_{object} = {D_{{object} + {air}} + {{ɛ_{object}( {D_{{object} + {air}} - D_{air}} )}( {\frac{d_{plates}}{d_{object}} - 1} )}}} & (8)\end{matrix}$

wherein D_(object) is the dissipation factor of the object 1660,D_(object+air) is the measured dissipation factor with the object inplace, and D_(air) is the measured dissipation factor with the objectnot in place.

When the size of the air gap and/or size of the object is not known orhard to measure, the permittivity of the object 1660 and/or thedissipation factor may be computed using the Two-Fluid Method. Under theTwo-Fluid Method, the capacitance of the object may be measured while ineach of two different fluids. Then the capacitance of each individualfluid may be measured. In some embodiments, one of the fluids may beair. The second fluid may be selected to have known and stabledielectric properties and not react with the test object. The dielectricconstant of the object may then be computed according to the equation:

$\begin{matrix}{ɛ_{object} = {ɛ_{air}\frac{\begin{matrix}{{C_{{object} + {fluid}}C_{{object} + {air}}( {C_{fluid} - C_{air}} )} -} \\{C_{fluid}{C_{air}( {C_{{object} + {fluid}} - C_{{object} + {air}}} )}}\end{matrix}}{C_{air}( {{C_{{object} + {air}}C_{fluid}} - {C_{{object} + {fluid}}C_{air}}} )}}} & (9)\end{matrix}$

wherein ∈_(air) is the relative permittivity of air, C_(object+air) isthe measured capacitance of the object when placed in air, C_(air) isthe measured capacitance of the air with the object not in place,C_(object+fluid) is the measured capacitance of the object when placedin the second fluid, and C_(fluid) is the measured capacitance of thesecond fluid with the object not in place.

The calculated relative permittivity of the object 1660 may then becompared to known values to determine the material of the object 1660.The known permittivity values for various materials may be saved in amemory, a database, or the like. Permittivity values for materials mayinclude permittivity values for compounds and/or composite materials.Each material may have a plurality of permittivity values saved fordifferent possible frequencies, temperatures, electrode angles,voltages, and times of exposure to an electric field. Alternatively,permittivity values for a default temperature and/or electrode angle maybe saved and permittivity values for other temperatures and/or electrodeangles may be computed from the default value. As previously discussedfor displacement measurements, continuous monitoring of the electrodes1631, 1632 during displacement measuring can be used to correct theeffect of the angled electrodes on the displacement. The dielectricrelaxation and/or dissipation factor for the material may also becalculated and saved in some embodiments.

A most likely material may then be selected by comparing measured valuesto corresponding saved values to find a best fit and/or minimize theerror between the saved values and the measured values. The sensor 1600a may continuously attempt to identify the material starting at lowestpossible voltage, current, and frequency values, so as to minimize theamount of energy applied to the object 1660. The voltage, current,and/or frequency may be increased incrementally either separately ortogether to measure the values of the capacitor as a function of thechange in voltage, current, and/or frequency. The sensor 1600 a may stopwhen a certainty or error in its decision reaches a predeterminedthreshold. In some embodiments, the sensor may use only the lowestpossible voltage, current, and frequency to identify the object 1660.

In embodiments, the saved permittivity values may be acquired throughdirect measurements of known materials using the sensor 1600 a. Thesensor 1600 a may not need to be calibrated in some embodiments whendirect measurements of the permittivity values are made. In otherembodiments, the permittivity values may be acquired from third partiesor measured in a laboratory. Laboratory measurements may be made usingan off-the-shelf measurement device, such as Hewlett-Packard's HP16451B. Alternatively, laboratory measured permittivity values for aplurality of frequencies, temperatures, and exposure times may be storedinitially, and measured permittivity values may be used to updatecorresponding values or may be extrapolated to provide additional valuesfor that material. Permittivity values may be measured for compoundsthat do not have readily available data.

Measured values may be used to determine deviations from an idealcapacitor, such as leakage; parasitic effects; breakdown voltage;temperature deviations; inherent inductance, resistance, or dielectricloss; and the like. Linear deviations, such as leakage and parasiticeffects, can be dealt with by adding virtual circuit components whencomputing capacitance from measured circuit properties, such asmagnitude and/or phase of voltage, current, and the like. Nonlineardeviations, such as breakdown voltage, may be saved separately andreferenced when analyzing measured circuit properties. Then, the powersource may be controlled to remain below the breakdown voltage. Forlinear deviations that change the capacitance value, such astemperature, or for parasitic effects that are non-uniform over varyingfrequency, such as inherent inductance, resistance, or dielectriclosses, the deviations can be accommodated by saving the amount ofdeviation for specific temperature or frequency values and/or bymodifying the saved permittivity values. The temperature deviation maybe saved as a capacitance deviation of parts per million per degreeCelsius and may be negative or positive.

Permittivity values for different purity levels of a material or forobjects that have hazardous materials on them may also be saved. Thepurity level of the object 1660 or existence of hazardous materials maythen be monitored continuously throughout the manufacturing process. Ifthe sensor 1600 a detects impurities or hazardous material, it may alertan operator or sound an alarm. The dielectric constant of the object1660 may be that of a chemical compound in these instances.

Once the material of the object 1660 is known, the pressure of a grippercomprising the sensor 1600 a may be adjusted to ensure sufficientfriction to hold the object while also ensuring the object 1660 is notdamaged by the gripper. In some embodiments, the pressure of the grippermay initially be minimal. Then, the sensor 1600 a may determine thematerial of the object. Once the material is known, properties, such asdensity, compressive strength, wall thickness, and the like for thematerial may be determined. Material properties may be saved in thememory or database storing the permittivity values. From the determineddensity, wall thickness, compound, and size measurements of the object1660, a weight of the object 1660 may be determined. The gripper maythen determine the pressure to be applied to the object 1660 andincrease the applied pressure to that value. In some embodiments, thegripper may apply the minimum pressure necessary to handle the object1660. If the minimum pressure necessary to manipulate the object maydamage the object 1660, the gripper may notify an operator, nonethelessapply the minimum pressure required for manipulation, and/or apply themaximum pressure that will not damage the object. For operations wherethe objects 1660 are a known size, a predetermined pressure may besaved.

Some energy may remain in the object 1660 after the voltage differentialhas been removed from the movable electrodes 1631, 1632 due topolarization of the dielectric. In some embodiments, the stored energyin the object 1660 may be dissipated once the relative permittivity isdetermined. To do so, the electrodes 1621, 1622, 1631, 1632 may beswitched back to measuring displacement. Because both plates of thecapacitor are resistively tied to ground, any stored potential energy inthe object 1660 may be dissipated. In alternate embodiments, both platesof the capacitor may be switched to ground for a predetermined period oftime. If the capacitor remains charged for a long period of time, it maynot completely discharge when briefly discharged due to dielectricabsorption (also referred to as soakage or battery action). To avoiddielectric absorption, the capacitor may be charged for only a limitedtime, and/or the length of time for any of the above methods ofdischarge may be determined based on the length of time the capacitorremains charged.

FIG. 16B is a schematic diagram of a resistivity sensor 1600 bcomprising opposing sensor cells 1611 b, 1612 b. The resistivity sensor1600 b may be configured in a manner similar to the relativepermittivity sensor 1600 a, but each sensor cell 1611 b, 1612 b maycomprise an additional external electrode 1671, 1672. In someembodiments, the external electrodes 1671, 1672 may be thin metal,conductive elastomer, conductive polymer, or thin film on the outside ofthe sensor cells 1611 b, 1612 b that can electrically couple to anobject (not shown). A power source 1640 b and electrical propertymeasuring device 1650 b may measure the resistance of the object in anyof the manners previously discussed for measuring resistance of theconductive fluid between the electrodes 1621, 1622, 1631, 1632. In someembodiments, the electrical property measuring device 1650 b may be usedfor measuring resistance of the object, measuring permittivity of theobject, measuring capacitance between the displacement sensingelectrodes 1621, 1622, 1631, 1632 (when a dielectric fluid is used fordisplacement measurement), and/or for measuring resistance of theconductive fluid between the electrodes 1621, 1622, 1631, 1632. Theresistivity measuring device may also be used to discharge potentialenergy stored in the object due to capacitance measurements.

Once the resistance is measured, the resistivity of the material maycomputed using the equation:

$\begin{matrix}{\rho = \frac{RA}{}} & (10)\end{matrix}$

wherein ρ is the resistivity of the material, R is the measuredresistance, A is the cross-sectional area of the object between theexternal electrodes 1671, 1672, and l is the distance between theexternal electrodes 1671, 1672. As with relative permittivity, thedistance between the external electrodes may be determined from thedisplacement measurements made according to previously discussedmethods. The area may be determined by characterizing the geometry ofthe object. In some embodiments, one or more additional sensor arrays(not shown) perpendicular to the sensor cells 1611 b, 1612 b may be usedto determine the area of the object. Alternatively, additional sensorcells (not shown) parallel to the sensor cells 1611 b, 1612 b may usepressure sensors measuring pressure of the conductive fluid to detectthe edges of the object. The determined resistivity may be compared tosaved resistivity values to identify the object's material in a mannersimilar to comparing permittivity values. Corrections to the measuredresistance may be made for internal sensor component resistances,temperature variations, and the like. Alternatively or additionally,resistivity values for a plurality of temperatures or a temperaturecoefficient may be saved.

Gallium Oxide Contacts

Gallium Oxide (Ga₂O₃) may be used to form a contact to which anelectrode may be attached, such as for small sensors on the millimeterto micrometer scale or less. The Gallium Oxide contacts may be used withpiston based sensor cells 610 and/or flexible wall sensor cells 110. TheGallium Oxide contacts may be used with sensor arrays with or withoutinternal insulating walls to separate sensors, such as the sensor arrays1000 or 1100. To create the contact, first, a microfluidic channel, suchas a cylinder, chamber, or the like, may be filled with a gallium alloyusing an applied pressure from, for example, a pump and/or capillaryforces. The microfluidic channel may have at least one opening and maybe filled until the gallium alloy reaches the opening.

The area outside the opening may comprise Argon gas to prevent thegallium from reacting with other elements. The pressure applied to thegallium alloy may be kept below a threshold where the gallium alloywould flow beyond the opening. The surface tension of the gallium alloymay form a round shape and/or the gallium alloy may be molded into adesired shape. Gallium oxide may then be caused to form on the galliumalloy. The gallium oxide may be formed through various methods: oxygenmay be added to or replace the argon gas and the gallium alloy may beheated while in contact with the oxygen; the gallium oxide may be formedby precipitating neutralization of acidic or basic solution of galliumsalt; gallium nitrate may be thermally decomposed; reaction oftrimethylgallium and oxygen may be used to form a thin film of galliumoxide covering the gallium alloy; pure gallium may be used to cover thegallium alloy using sputtering or the like with the gallium oxide formedfrom the pure gallium; or the like.

Once a sufficiently sized layer of gallium oxide has been formed, amovable electrode may be coated onto the gallium oxide film, and/or thegallium oxide may be used as a movable electrode. In some embodiments,the movable electrode may be subdivided into multiple electrodes sharingthe gallium alloy liquid in common. One or more fixed electrodes may bemounted on the other end of the microfluidic channel in a configurationsimilar to the sensor array 1000 and/or the sensor array 1100. In someembodiments, the electrodes may be tungsten, tantalum, columbium,titanium, molybdenum or the like. The electrodes may be attached usingsputtering, ink jet printing, screen-printing, deposition, etching, orthe like.

The electrodes may be connected with a wire to an integrated circuit onor off the sensor cell 110, 610 to apply power and/or measure electricalproperties of the sensor cell 110, 610. Then, the electrode may becovered with an insulating and nonconductive material to preventaccidental electrical contact. Another layer of gallium oxide may beapplied on top of the electrode, or silicon rubber may be applied to theelectrode. The gallium oxide or silicon rubber may be added usingsputtering, ink jet printing, screen-printing, deposition, etching, orthe like. The sensor cells constructed according to this method may beconnected in series with additional sensor cells and/or in series withan electric motor and/or configured into modules, such as the touchsensor 700 or the touch sensor 800.

Weight Measurement

The gripper may measure the mass or weight of the object. The mass or adensity computed from the mass may allow a more accurate determinationof the composition of the object. The gripper may measure the mass byreleasing the object on a scale or balance and re-grasping the objectonce the measurement is complete. Alternatively, the gripper may beintegrated into a balance or scale. The weight or mass of the object maybe computed by subtracting the weight of the gripper without the objectfrom the weight with the object, zeroing the balance or scale to accountfor the gripper weight, or the like. The balance or scale may be ananalytical balance, an analytical scale, a strain gauge scale, or thelike. A strain gauge may comprise a beam with a length-sensitiveelectrical resistor. Variations in the resistance due to deflections ofthe beam may be measured to determine the weight or mass.

Packaging of Grippers and Sensors

Various packages are possible for the grippers and sensors discussedherein. In a gripping system, multiple grippers and/or tools mayinteract with each other. For example, one gripper may hold an objectwhile another gripper performs a manufacturing operation on the object.The manufacturing operation may be screwing two objects together,inserting the object into something else, or other specificmanufacturing operations. Alternatively, one gripper may transfer anobject to another specialized gripper to perform a specific operation.For example, an object may be grasped from the outside by a firstgripper and then transferred to a gripper that grasps from the inside,which will allow for insertion of the object and the like.

In some embodiments, the gripper may be packaged to perform apredetermined operation. In other embodiments, the packaging may bedesigned to perform a more universal functionality. The packaging forthe gripper may be similar to a human hand in shape and/or function. Fora hand shaped gripper, sensors may be embedded into the fingers andpalm. Alternatively, the sensors may be mounted on a holding fixture toindicate the object's location. Various tasks may be performed by agripper with predetermined packaging or a universally packaged gripper,such as grasping, securing, measuring, manipulating, and/or recognizingobject. Various properties may be measured to recognize the object, suchas dimensions, weight or mass, dielectric constant, dissipation factor,dielectric relaxation, resistivity, and the like. Such measurements mayallow for a good approximation of the object's properties, which mayallow for more accurate manipulation. Multiple sensors may share acommon conductive fluid and/or insulating flexible walls in someembodiments. By using a single insulating flexible wall over many cells,pistons and shafts of movable electrodes may be stabilized, contaminantsmay be eliminated between sensors, and performance of a robotic hand maybe improved. Alternatively, or in addition, the contact cells may bestacked closely together to eliminate contaminants and reduce the areaof the sensor walls that contain the sensors and do not performelectrical functions. The walls of the sensors may be minimized tominimize the area between electrical sensors.

FIG. 17 is a schematic diagram of a gripper package 1700 comprisingactuators 1721, 1722 (e.g., electric motors, linear hydraulic actuators,or the like) in series with displacement sensors 1711, 1712. In theillustrated embodiments, there may be two displacement sensors 1711,1712 and/or arrays of displacement sensors and two correspondingactuators 1721, 1722, but one to six displacement sensors or more, eachcontaining one or more modules and/or each with corresponding electricmotors, may be used in other embodiments. The actuators 1721, 1722 maybe electric motors able to position the displacement sensors 1711, 1712very accurately with lead screws through small incremental movements ofmeasurable displacements. The actuators 1721, 1722 and displacementsensors 1711, 1712 may be mounted on a rotating indexing table and/or atable 1740 that can adjust the angle of the object. Actuators 1731,1732, 1733, 1734 (e.g. electric motors) located at the edges of thetable 1740 may adjust the table 1740. Such tables may be available fromHass Automation Inc. and IntelLiDrives Inc.

The distance of the movement of the lead screw may be added to themovement of the displacement sensors to compute the total movement ofeach sensor. The displacement sensors 1711, 1712 may comprise multiplesensor cells in parallel and series with each other, and the sensorcells in series may be summed to compute the movement of thedisplacement sensors. The total displacement may be used to calculatethe geometry of an object being grasped. For very small objects,including microelectromechanical systems (MEMS) and microfluidicdevices, the displacement sensors 1711, 1712 may comprise a single layerof sensor cells. The sensor cells in the single layer may share a singleflexible wall subdivided into multiple electrodes as illustrated in FIG.11. Feedback from pressure sensors in the displacement sensors 1711,1712 and/or the displacement calculations may be used to accuratelycontrol movement of the actuators 1721, 1722, such as electric motorsand lead screws, to a millionth of an inch. Calibration and measurementsmay be performed in a manner similar to method 900.

In other embodiments, the displacement sensors 1711, 1712 may beattached to the end of robotic arms (not shown) as end effectors. Therobotic arms may be able to move the displacement sensors 1711, 1712 tomultiple locations on an object. This may allow displacementmeasurements to be made around the entire object to completely map thesurface of the object. Alternatively, measurements may be made until amaterial of the object is determined. A rotating indexing machine (notshown) may also or alternatively be used to rotate the displacementsensors 1711, 1712 and/or the object for measuring and manipulation. Forrotating robotic arms, the distance displaced by the displacementsensors 1711, 1712 through robotic arm movement may be computedaccording to the equation:

S=Θr  (11)

wherein S is the distance displaced, Θ is the angle in radians, and r isthe radius of the rotation. The net displacement in two orthogonal axesmay be computed according to the equations:

S _(X) =r cos Θ  (12a)

S _(Y) =r sin Θ  (12b)

wherein S_(X) is the net displacement in a first axis and S_(Y) is thedisplacement is the net displacement in a second orthogonal axis.Robotic arms may be available from KUKA Robotics Corp., Yaskawa MotomanRobotics, and FANUC Robotics, and indexing machines may include the TRSeries from Ganro Industrial Corp. Alternatively, a radially movinghydraulic joint may be used.

The displacement sensors 1711, 1712 may also be incorporated into thehands (not shown) of a robot (not shown). The sensors may be located onall sides of the robotic hands. Two hands from separate arms may be usedto enclose an object for pattern recognition, displacement measurements,capacitance measurements, and material determinations. The hands mayfurther comprise fingers (not shown) that can be inserted into smallerplaces. In some embodiments, the hands and/or fingers on each hand maydirectly oppose one another to make measurements. In other embodiments,the hands and/or fingers may be at known angles. For performingcapacitance measurements and the like, circuits from each hand may runto a common location, such as a controller or base station (not shown)to complete the circuit.

FIG. 18 is a side view of a quick-release gripping system 1800 with across-sectional view of a rotary joint 1840. A fixed dimension grippermay comprise a pair of gripping sensor arrays 1810, 1820 with a maximumopening into which an object 1860 may be inserted. The fixed dimensiongripper may grip the object 1860 from the inside or from the outside.The fixed dimension gripper may further comprise object constrainingblocks 1831, 1832. In other embodiments, the object constraining blocks1831, 1832 may be replaced by additional gripping sensor arrays 1810,1820.

The rotary joint 1840 may be used to deliver a fluid to the object 1860and/or to control the hydraulic cylinders in the sensor arrays 1810,1820. The fluid may be water, oil, paint, conductive fluid, dielectricfluid, or the like. The rotary joint 1840 comprises a sheath 1844 withstationary inlets 1841 into which fluids may be input from stationarysources. Rotational outlets 1843 may output the fluids to the object1860, and/or fluid transfer may be used in the sensors or grippers 1810,1820. The rotational outlets 1843 may be rotated without disrupting theflow of fluids. Conversion holes 1842 may rotate with and transfer fluidto the rotational outlets 1843 while also accepting fluids from thestationary inlets 1841 via cyclical chambers. In embodiments, the rotaryjoint 1840 may also be able to transfer electrical or optical powerincluding data using silver coated ball bearings, wire brush, conductiverings, liquid metal, or the like. Exemplary rotary joints 1840 may bethe FO197 from Moog Corporation or Multiple Passage Systems from RotarySystems, Inc.

FIG. 19 is a side view of a quick-change turret 1900 that may comprise arotary joint 1840. The quick-change turret 1900 may comprise a pluralityof tools 1910, 1920, 1930, 1940, such as a drill 1910, a deburring tool1920, a welding unit 1930, a fluid nozzle 1940, end mills (not shown),vacuum grippers (not shown), conventional grippers (not shown), and thelike, to operate on an object. The tools 1910, 1920, 1930, 1940 may beexchanged with the quick release gripping system 1800 within a roboticarm. One gripper, such as gripper 700, 800 b, 1100, 1700, 1800, or thelike, may secure an object while the robotic arm uses the tools 1910,1920, 1930, 1940 to perform operations on the object. It will beunderstood by those of skill in the art that several grippers and/orrobotic arms may operate on a single or multiple objects at the sametime and that grippers may be exchanged for tools.

The tools 1910, 1920, 1930, 1940 may be located on a turret head 1950,while a neck 1960 may comprise a rotary joint 1840. In some embodiments,the quick-change turret 1900 may further comprise one or more grippingsensor arrays. In some embodiments, a quick-release gripping system 1800may act as a vice while the quick-change turret 1900 operates on theobject or transfers tools to another gripper for operations on objects.If the quick-change turret 1900 comprises gripping sensor arrays, thequick-change turret may insert the object in and remove the object fromthe quick-release gripping system 1800. For a quick-change turret 1900with gripping sensor arrays, a rotary joint 1840 for the quick-changeturret 1900 may be required to rotate in at least one axis, transferelectrical power, transfer fluid, transfer data, open and close thegripper, and the like.

A tool 1910, 1920, 1930, 1940 may be selected by rotating to the propertool and/or by folding down the tool of interest using hinges 1911,1921, 1931, 1941. Tool selection may be controlled hydraulically,electrically, and/or pneumatically. A processor (not shown) may controloperation of the quick-change turret 1900 including positioning andwhich tool 1910, 1920, 1930, 1940 to use. As a gripping system 1800grasps and recognizes an object or is exchanged for a tool 1910, 1920,1930, 1940, the processor may determine which tool 1910, 1920, 1930,1940 to use and begin operating on the object, which may be held byanother gripper. The gripping system 1800 may be exchanged for a tool1910, 1920, 1930, 1940, or the gripping system 1800 may grasp a tool1910, 1920, 1930, 1940.

FIG. 20 is a cross-section view of a cam driven robotic gripper 2000with a cam guide 2020 for manipulating gripping sensor arrays 2030,2040, 2060. The gripping sensor arrays 2030, 2040, 2060 may comprise twocam-controlled jaws 2030, 2040 that grip with a base 2060. To manipulatethe jaws 2030, 2040, an electric motor 2013 may turn a lead screw 2010.Two oppositely threaded nuts 2011, 2012 may move towards each other oraway from each other depending on the direction the electric motor 2013turns. Additionally or alternatively, the lead screw 2010 may haveopposite threads on each side of its center point. The nuts 2011, 2012may be attached to guide pins 2021, 2022 or guide balls located withinthe cam guide 2020. The guide pins 2021, 2022 also may be moved towardsor away from each other with the operation of the electric motor 2013.Alternatively, the jaws 2030, 2040 may be manipulated by hydraulicdisplacement sensors, such as the sensor 600, to move the cam guides2021, 2022, and the nuts 2011, 2012 may or may not be connected to theend of the piston shaft. One or more connecting lines 2050, such aswire, hinges, metal, or the like, may connect the guide pins 2021, 2022to the jaws 2030, 2040 using bolts 2031, 2032, 2041, 2042, screws, pins,or the like. The connecting lines 2050 may be complex hinges thatcomprise multiple joints.

Different sections 2023, 2024, 2025, 2026, 2027 of the cam guide 2020may be configured to angle the jaws 2030, 2040 in different directions.For example, when the guide pins 2021, 2022 are in section 2027, thejaws 2030, 2040 may be at a 90 degree angle to the base 2060. As theguide pins 2021, 2022 pass through section 2023, the jaws 2030, 2040 mayrotate until they are parallel with the base 2060. In section 2024, thejaws 2030, 2040 may move laterally while continuing to be parallel withthe base 2060. Section 2025 may move the jaws 2030, 2040 rotationally toreturn them to a 90 degree angle relative to the base 2060. Finally,section 2026 may cause the jaws 2030, 2040 to return to parallel withthe base 2060 and to close on the base 2060 so sensors in the sensorarrays 2030, 2040, 2060 are completely covered.

Different sections 2023, 2024, 2025, 2026, 2027 may allow the gripper2000 to perform different functions. For example, while the jaws 2030,2040 are at 90 degree angles in section 2027, the gripper 2000 may beable to close on an object and hold it like a vice. In section 2024,when the jaws 2030, 2040 may be parallel to the base 2060, the gripper2000 may be able to interact with another gripper (not shown) to graspan object too large for the gripper 2000 to hold by itself. By returningthe guide pins 2021, 2022 to section 2023 while grasping the largeobject, the jaws 2030, 2040 can be angled to improve the grip on theobject. Pressure sensors in the sensor arrays 2030, 2040, 2060 mayensure that pressure is distributed evenly on the object, which willmake the gripper 2000 self-centering. During section 2026, when thesensors are covered, the sensor arrays 2030, 2040, 2060 may be protectedfrom damage or contamination. In some embodiments, there may be morethan one cam guide 2020, such as a cam guide (not shown) on the lowerend of the jaws 2030, 2040, which may have angles to account for theturning of the jaws 2030, 2040. The jaws 2030, 2040 can be furtherseparated into separate fingers (not shown), which may be controlled byhydraulically, pneumatically, electrically, or the like. The fingers maymove independently or together to grasp smaller objects or performintricate operations before or after the gripper has identified theobject being manipulated.

FIGS. 21A, 21B, 22A, 22B, 23 are side perspective views of a roboticgripper 2100 comprising lead screws 2121, 2122 to adjust the position ofsensor array panels 2130, 2140, 2160. In some embodiments, the leadscrews 2121, 2122 may be pistons of a linear hydraulic actuator. FIGS.21A and 21B are side perspective views of the robotic gripper 2100 whenthe side sensor array panels 2130, 2140 are in a flat position. FIGS.22A and 22B are side perspective views of the robotic gripper 2100 whenthe side sensor array panels 2130, 2140 are perpendicular to the bottomsensor array panel 2160. FIG. 23 is a side perspective view of therobotic gripper 2100 when the side sensor array panels 2130, 2140 are inan acutely angled position. In the illustrated embodiment, knobs 2111,2112 control the turning of the lead screws 2121, 2122. In alternateembodiments, motors, cranks, pulleys, or the like may be used to turnthe lead screws 2121, 2122, and/or hydraulic cylinders, pistons, andshafts may be used instead of or in addition to the lead screws 2121,2122. A processor (not shown) may control movement of the lead screws2121, 2122. The processor may secure an object (not shown) with thegripper and use information gathered from the sensor array panels 2130,2140, 2160 to determine how to operate on the object with anothergripper and/or tool (not shown).

The lead screws 2121, 2122 may be coupled to the side sensor arraypanels 2130, 2140 by braces 2135, 2145. Both lead screws 2121, 2122 maybe turned simultaneously in a similar direction to cause the braces2135, 2145 and the side sensor array panels 2130, 2140 to move laterallytowards or away from the bottom sensor array panel 2160. Both leadscrews 2121, 2122 may be turned in contrasting directions and/or onlyone lead screw 2121, 2122 to cause the braces 2135, 2145 to rotate aboutrespective rotational axes 2131, 2141. The braces 2135, 2145 may rotatethe side sensor array panels 2130, 2140 relative to the bottom sensorarray panel 2160. Each brace 2135, 2145 may also include a rod 2132,2142 configured to interface with one or more channels 2150. The one ormore channels 2150 may support the rods 2132, 2142 and/or constraintheir movement to a desired path.

Integrated Robot Power Source

Mobile robots may be powered by a battery. There may be a tradeoffbetween the capacity of the battery and the total weight and/or thetotal volume of the robot. The energy capacity per unit volume of therobot may be referred to as its energy density and the energy capacityper unit mass of the robot may be referred to as its specific energydensity. For some robots, a battery of suitable weight and volume mayprovide less than an hour of operating time. To save weight and volume,batteries may be incorporated into structural components of the robot toserve a structural function in addition to providing energy. Suchincorporation may allow for increased energy density and/or increasedspecific energy density. For a robot with a predetermined weight and/orvolume, the increased energy density and/or specific energy density maytranslate into an increased operating time. Structural components maycomprise skin, walls, skeletal components, and/or the like. Otherapplications for integrated power sources may include powering electricvehicles. For example, batteries may be included in the vehicle's bodypanels or frame.

FIGS. 24A and 24B are cross-section views of skin panels 2400 a,bconfigured to power a robot, such as to power a robotic gripper, topower robot mobility, and/or the like. In some embodiments, the skinpanels 2400 a,b may comprise a battery 2420 to store electricity andprovide power when required. The battery 2420 may comprise an anode2421, a cathode 2422, and a separator/electrolyte 2423. The battery 2420may be surrounded by a wall 2410 that holds and protects the battery2420. As a result, separate packaging is not required for the battery2420, which can save weight and space and produce a high energy densityand/or a high specific energy density for the robot.

Wires 2431, 2432 may connect the battery 2420 to external components.The wires 2431, 2432 may be connected to both a charging and adischarging apparatus and/or both a charging and a discharging port. Thewires 2431, 2432 may connect to other batteries, positive and negativebattery contact points, input and output power ports, or robot elements.The wires 2431, 2432 may connect to a quick release contact for externalconnection of the battery 2420 to other batteries, a charging powersource, a discharging power drain, or the like. The wires may beincorporated into a contact element, such as one known to those of skillin the art. In some embodiments, the wall 2410 may completely surroundthe battery with the wires 2431, 2432 perforating the wall 2410 as theonly external connections to the battery 2420.

The skin panels 2400 a,b may be molded into a desired shape. Forexample, the skin panels 2400 a,b may be shaped to conform to and encaseor cover body parts of a robot, such as the legs, arms, torso, body, orthe like. A plurality of skin panels 2400 a,b may be fastened to oneanother to assemble an entire skin to cover the robot. For example, apair of skin panels 2400 a,b may be two halves configured to encircle anindividual body part. The skin panels 2400 a,b may be fastened togetherby various methods including screw and bolt, clips, or the like.

The wall 2410 may be rubber, silicon, polymer, polycarbonate polymer, orthe like. The wall 2410 may be a flexible wall. The wall 2410 maycomprise multiple layers with different layers configured to performdifferent functions. The materials that the wall 2410 is comprised ofmay be selected to provide a desired flexibility or rigidity and/orother desired properties. In some embodiments, the battery 2420 mayignite and/or explode when punctured or damaged. Accordingly, the wall2410 may be configured to flow, elongate, and/or expand to enter andseal any punctures. The sealed punctures may be electrically isolated bythe wall 2410 to prevent short circuits between cells or other hazardousconditions. Alternatively, or in addition, the wall 2410 may include anouter layer comprising a polycarbonate resin thermoplastic, such asLexan®, to prevent punctures or damage to the battery 2420.

In some embodiments, the battery 2420 may be a rechargeable lithiumbattery, such as a lithium polymer battery, a lithium ion battery,and/or a thin film lithium battery. The battery 2420 may be shaped toconform to the radius and/or angle of a desired body part. The battery2420 may be formed and shaped by injection molding, deposition, and/orthe like. The anode 2421, cathode 2422, and/or separator/electrolyte2423 may be flexible and/or may comprise a plurality of layers. In someembodiments, the wall 2410 may be formed over the battery 2420.Alternatively, the battery 2420 may be inserted into a preformed wall2410. The battery 2420 may comprise a plurality of battery cells. Thebattery cells may be off-the-shelf products, such as those produced byLeyden Energy Inc., Quallion LLC, LG Chem Power, Johnson Controls, orA123 Systems. The battery cells may be wired in parallel and/or seriesto achieve a desired voltage and energy capacity. Further, batteries2420 from multiple panels 2400 a,b may be wired together in paralleland/or series to increase the voltage and/or energy capacity.

The battery 2420 may include a pressure sensor (not shown) configured todetect increases in pressure, which may be indicative of a dangerousbuild up of gases. Charging may be interrupted or stopped when thepressure exceeds a predetermined level. The pressure sensor may bepiezoresistive, PVDF, hydrostatic, a liquid column, aneroid, Bourdon,diaphragm, bellows, air pressure gradient, optoelectronic, Fabry-Perot,a strain gauge, a Pirani vacuum gauge, a capacitive pressure sensor, orthe like. The battery 2420 may also or instead include a pressure reliefvalve (not shown) configured to release gases building up in the battery2420 when a relief pressure is exceeded. The battery 2420 may include atemperature sensor configured to monitor battery temperature duringcharging and discharging. The battery-charging profile may be adjustedbased on the detected temperature.

FIG. 25 is a cross-section view of a skeletal component 2500 comprisinga plurality of integrated batteries 2520, 2530. The skeletal componentmay comprise an inner core 2510 around which the plurality of batteriesare wrapped. The inner core 2510 may be elongated and cylindrical, suchas tube and/or pipe shaped, in some embodiments. The inner core 2510 maycomprise a strong and/or light-weight material such as titanium,tungsten, osmium, carbon fiber, aluminum, magnesium, and/or the like.The high strength material may maintain stability and decrease thepossibility of deformation of the inner core 2510.

The inner core 2510 may comprise a hollow interior section 2515 throughwhich wires, fluids, or the like may be passed. Much of theinfrastructure for a robot may be incorporated into the inner core 2510including electric power transfer, fluid power transfer, data transfer,monitoring and control components, and the like. Monitoring and controlcomponents may include pressure and/or temperature sensors for thebatteries 2520, 2530, multiplexers, fluid flow meters, switches tocontrol charging and discharging of the batteries 2520, 2530, voltagemeters for the batteries 2520, 2530, and the like. The wires may couplethe batteries 2520, 2530 to electric motors, hydraulic pumps, charginginterfaces, processing units, and/or the like, and/or the wires maytransmit data between various components of the robot. The fluid may betransmitted by a hard plastic pipe, such as a polyvinyl chloride (PVC)pipe, polycarbonate polymer, or the like, that is encircled by the innercore 2510. The PVC pipe may reinforce the inner core 2510.Alternatively, the fluid may be transferred with no additional tubing.In some embodiments, the inner core 2510 may act as a hydraulic cylinderwith a piston and a rod and with fill and drain sections as previouslydescribed. Data and power may be transferred via a separate tube, whichmay or may not be within the inner core 2510 and may run though thecenter of the piston and shaft if included. The fluid may be pressurizedto strengthen the inner core 2510.

The core 2510 may be substantially circumscribed by an inner battery2520. The inner battery 2520 may substantially conform to the shape ofthe core 2510. A plurality of base plates 2511 may surround the core toprovide support and structure to the inner battery 2520 and the core2510. Additionally, support plates 2512 may separate the inner battery2020 into a plurality of sections and/or encase individual batterycells. The base plates 2511 and/or support plates 2512 may also comprisestrong and/or light-weight materials such as those previously discussed.An individual battery cell may occupy multiple sections, and/or anentire battery cell may be in a single section. For example, in theillustrated embodiment, four battery cells occupy twelve sections toform the inner battery 2520. In alternate embodiments, twelve separatebatteries may be contained in the twelve sections or different desiredmultiples may be used. The individual sections may be stacked togetherto encircle the inner core 2510. A fill material 2513, such as athermoplastic or the like, may fill gaps between battery windings withina section to create a smooth concentric outer surface. In otherembodiments, there may be no base plates 2511 and/or support plates2512, and the inner battery 2520 may be wound concentrically around theinner core 2510. The outer battery 2530 may be wrapped around the smoothconcentric outer surface and substantially circumscribe the innerbattery 2520. The outer battery 2530 may be enclosed in a casing (notshown). The casing may be a non-conducting material, such as plastic,rubber, or the like. In an embodiment, the outer casing may be apolycarbonate polymer, such as Lexan®.

The outer battery 2530 and/or the cells of the inner battery 2520 may becoupled in series and/or parallel to achieve a desired voltage and/orelectrical charge capacity. Similarly, the number of cells or the sizeof the batteries may be adjusted to achieve a desired capacity. Somebatteries, such as lithium or lithium ion batteries, may becomedangerously overcharged if the cells are charged unevenly. Accordingly,the batteries 2520, 2530 may be discharged and recharged in a mannerthat equalizes the voltage among batteries. For example, discharging andrecharging may be controlled by power switching between charging and/ordischarging individual battery cells. Such power switching may alsoallow for charging and discharging of cells with different voltagesand/or capacities. Each individual battery cell may be controlled by acorresponding switch. Battery cells that are determined to beovercharged may be removed from charging. Overcharging may be detectedfrom voltage measurements, gas pressure measurements, temperaturemeasurements, or the like. Voltage monitoring may be used for appliedcharging voltage control and/or for regulation of voltage throughswitching. Control circuitry for charging and discharging may beconnected to the batteries 2520, 2530 by wires that pass through thehollow section 2515 of the inner core 2510, and/or the control circuitrymay be integrated into the batteries 2520, 2530.

FIGS. 26A and 26B are front perspective views of different types ofbattery windings. A concentric battery winding 2600 a may be wrappedabout itself to form a plurality of layers. Alternatively, a parallelbattery winding 2600 b may comprise a plurality of substantiallyparallel, stacked layers. In other embodiments, windings may beperpendicular to each other. The direction of the winding may bereferred to as its grain and/or grain structure. The grain structure ofthe battery windings 2600 a, 2600 b may be chosen to reinforce andstrengthen the skeletal component. In an embodiment, the inner battery2520 may include the parallel battery winding 2600 b, and the outerbattery 2530 may include the concentric battery winding 2600 a. Thewinding 2600 a of the outer battery 2530 may be substantiallyperpendicular to those of the inner battery 2520 to increase strength.Alternative battery designs, such as prismatic grids, may also orinstead be incorporated into the winding design.

FIGS. 27A and 27B are cross-section views of sections 2700 a, 2700 b ofthe inner battery 2520. The windings 2710 a, 2710 b in each section 2700a, 2700 b may be insert molded into that section to most efficiently usethe space. The sections 2700 a, 2700 b may be assembled about the innercore 2710 to form the inner battery 2720. FIG. 27C is a cross-sectionview of a winding layer 2740 comprising an anode 2741, a cathode 2742,and an electrolyte 2743. Anode and cathode wires 2711 a,b and 2712 a,bmay be coupled to the anode 2741 and the cathode 2742 respectively andmay protrude from the sections 2700 a, 2700 b to provide externalconnections to the battery cells. The wires 2711 a,b and 2712 a,b maycouple battery cells to each other and/or may connect to other robotcomponents, charging ports, and/or discharging ports. A single pair ofnegative and positive leads may couple the skeletal component to otherrobot components, or there may be multiple pairs of leads for thebatteries 2520, 2530 or sections 2700 a, 2700 b. Battery components maybe available from Leyden Energy Inc., Quallion LLC, LG Chem Power, 3M,Johnson Controls, and A123 Systems.

The windings 2710 a, 2710 b may be tightly wound in the sections 2700 a,2700 b to most efficiently use the space in the sections 2700 a, 2700 band to increase the strength of the skeletal component 2500. The fillmaterial 2513 may add to the strength and density as well as maintainthe windings 2710 a, 2710 b in a tightly wound position. The packing ofthe sections 2700 a, 2700 b about the inner core 2510 may also beperformed within very tight tolerances to maximize the density andstrength of the skeletal component. Additionally, the wires 2711 a,b and2712 a,b may be fed through a close tolerance tube or pipe. The tube maybe made of a material comprising titanium, graphite, carbon fiber,and/or the like. For lithium polymer or lithium ion batteries, the innerand outer batteries 2520, 2530 may be able to flex thereby absorbingexternal stresses and reducing stresses on the inner core 2510. Thus,the structural stability of the inner core 2510 may be preserved despitesignificant flexing or bending of the outer layers of the skeletalcomponent 2500.

FIG. 28 is a front perspective view of a battery 2800 comprising aheating element 2840. The battery 2800 may have a limited operatingtemperature range outside of which the performance of the batterydegrades. The heating element 2840 may be configured to maintain thebattery 2800 within the operating range. For example, the heatingelement 2840 may be a resistive heating element comprising a resistivewire. Alternatively or in addition, a thermoelectric element may beconfigured to cool and/or heat the battery 2800.

The heating element 2840 may wrap around the outer battery 2820 but beinside the casing 2830. Alternatively or in addition, the heatingelement 2840 may wrap around the inner core 2810. The base plates 2511and/or support plates 2512 may comprise the heating element 2840 in someembodiments, and may be combined with an outer heating element in thecasing 2830 to seal the heated battery environment. The heating elementmay be as close to the battery as possible while still beingelectrically insulated from the battery. The heating element may beround, such as being helically shaped, or it may also be square,rectangular, or the like. Heating elements 2840 may be used with skinpanels comprising batteries and/or skeletal components with batteries.

Additionally, heating elements 2840 may be used with the displacementsensor cells. The precision of the displacement sensor cells may beaffected by changes of temperature. Accordingly, the heating elements2840 may increase the operational range of the gripper by maintainingthe gripper at a substantially constant temperature. The temperaturecontrol of the gripper may be maintained by heating the conductive ordielectric fluid inside a reservoir, by a heating blanket in contactwith the electrodes, and/or with heating elements embedded in the casingor skin of the gripper. For example, the gripper may include resistivewire and/or elements in the fluid reservoir and/or the gripperenclosure. Alternatively, the gripper may grasp a heating element,and/or a heat blanket, heated gloves, or clothing with heating elementsmay be applied to sections of a mobile robot. Temperature sensors in thegripper contacts, gripper enclosure, battery, joints, and/or the fluidreservoir may monitor the gripper and its components to accurately sensethe temperature and allow corrections to the temperature to be made.Alternatively or in addition, for a sensor cell with an electrolyte,conducting fluid, such as a KCI electrolyte, or a dielectric fluid, theoperating temperature range may be adjusted by changing the molarconcentration of the electrolyte or by the addition of antifreeze.

Joints and Skeletal Components

A skeleton for a robot may include a plurality of joints and skeletalcomponents configured to provide form and structure to the robot. Theskeletal components may include an inner core with male and/or femaleends. The inner core may couple to and/or include an end cap, couple toother skeletal components, couple to one or more joints, and/or thelike. The skeletal component may provide support and allow for thetransfer of fluid, electrical power, data, or the like. The joints maycouple together skeletal components and allow movement in one or moredegrees of freedom. The joints may allow skeletal components to rotaterelative to one another in a manner similar to the bones in a human bodyrotating about a joint. For example, the joints may be configured tomove skeletal components in a manner similar to the movement of fingers,elbows, waists, knees, wrists, shoulders, and/or the like. Other jointsmay also be included to allow the robot to perform any desired movement.The joints may include end caps to allow them to interface with theskeletal components.

In an embodiment, the robotic joint may be composed of three sectionsassembled and held together by a rotating connector. The rotatingconnector may couple and transfer fluid power, electrical power, and/ordata. FIGS. 29A and 29B are front and top perspective views of arotational hydraulic joint 2900. The rotational hydraulic joint 2900 mayinclude a center shaft 2930 and two outer shafts 2910, 2920 extendingradially from a cylindrical coupling 2940, which couples the centershaft 2930 to the two outer shafts 2910, 2920. The cylindrical coupling2940 may allow the center shaft 2930 to rotate relative to the two outershafts 2910, 2920. The rotational joint may be constructed of a highstrength material, such as polycarbonate polymer, titanium, steel,aluminum, or the like.

A pin 2945 through the center of the cylindrical coupling 2940 may bethe axis about which the center shaft 2930 rotates. The pin 2945 may bea rotary joint, such as rotary joint 1840, configured to transfer fluid,hydraulic power, electrical power, data, and/or the like between theouter shafts 2910, 2920 and the center shaft 2930. Alternatively, thepin 2945 may be a simple rod that does not transfer any fluid, hydraulicpower, electrical power, or data. The pin 2945 may include bearings tofacilitate rotation.

The center shaft 2930 may couple to a first skeletal component (notshown) and the outer shafts 2910, 2920 may couple to a second skeletalcomponent (not shown) and allow the skeletal components to rotaterelative to one another. The high strength joint 2900 may couple to highstrength inner cores of the skeletal components. Alternatively, thecenter and/or outer shafts 2910, 2920, 2930 may couple to one or moreadditional joints to create a composite joint with multiple degrees offreedom. The center shaft 2930 may include a male end configured to matewith a female end of a skeletal component, and the outer shafts 2910,2920 may couple to an end cap with a female end configured to mate witha male end of a skeletal component. Alternatively, the center and/orouter shafts 2910, 2920, 2930 may be configured to mate with male and/orfemale ends of the skeletal components instead.

The cylindrical coupling 2940 may be hydraulically actuated to causerotation of the center shaft and may measure the extent of rotation. Thecylindrical coupling 2940 may include two torus-shaped cavities 2950,2960. In other embodiments, the cylindrical coupling 2940 may includeone cavity or three, four, or more cavities. The joints may act as twohydraulic cavities 2950, 2960. One cavity 2960 may extend the joint andthe other cavity 2950 may retract the joint. Approximately one half ofeach cavity 2950 a, 2960 a may be in the outer shafts 2910, 2920, andthe mating half for each cavity 2950 b, 2960 b may be in the centershaft 2930. Pistons 2952, 2962 in each cavity 2950, 2960 may bepermanently attached to the center shaft 2930. The center shaft 2930 maybe a part of the piston 2952, 2962 and shaft. The center shaft 2930 maybe an extension of the piston shaft and piston 2952, 2962. End caps2954, 2964 may be permanently attached to the outer shafts 2910, 2920.Referring also to FIGS. 29C-F, each cavity 2950, 2960 may include thepiston 2952, 2962, the bladder end cap 2954, 2964, and a bladder 2956,2966. The pistons 2952, 2962, which are illustrated in FIG. 29E, mayboth be affixed to and/or integrated into the center shaft 2930 to causethe center shaft 2930 to rotate when the pistons 2952, 2962 move withinthe cavities 2950, 2960. The bladder end caps 2954, 2964, which areillustrated in FIGS. 29C and 29D, may be stationary relative to theouter shafts 2910, 2920. The bladders 2956, 2966 may each be permanentlyaffixed at one end to their respective piston 2952, 2962 and permanentlyaffixed at the other end to their respective bladder end cap 2954, 2964.The bladders 2956, 2966 may be attached and/or sealed to the pistons2952, 2962 and bladder end caps 2954, 2964 by mechanical means, chemicalmeans, and/or the like.

In the illustrated embodiment, a retraction cavity 2950 may beconfigured to cause the center shaft 2930 to retract towards the outershafts 2910, 2920 when the retraction bladder 2956 is filled with fluid,and an extension cavity 2960 may be configured to cause the center shaft2930 to extend away from the outer shafts 2910, 2920 when the extensionbladder 2966 is filled with fluid. In each case, as the bladder 2956,2966 is filled, the opposing bladder 2956, 2966 may be permitted toempty and compress (not shown). The compressed bladder 2956, 2966 mayfold inside itself and around the piston 2952, 2962 as it is compressed.In other embodiments, one cavity may perform both extension andretraction. Smaller joints may have less fluid leakage when two or morecylinders are used. During expansion or compression of the bladders2956, 2966, the cavities 2950, 2960 may ensure that the bladders 2956,2966 retain their shape. The bladders 2956, 2966 may be fitted into asleeve that moves with the bladder to prevent counter rotationalfriction (not shown). Fill and/or drain ports (not shown) may allowfluid to be added and removed from the bladders 2956, 2966. The fluidmay be carried by hoses and/or pipes (not shown) external to the joint2900 and/or by cavities and/or channels (not shown) in the center and/orouter shafts 2910, 2920, 2930. Thus, movement of the joint and anyattached skeletal components may be controlled via hydraulic actuation.

The cavities 2950, 2960 may each form a hydraulic measuring cell. Thepistons and shafts 2952, 2962 may each include a movable electrode 2953,2963, and the bladder end caps 2954, 2964 may each include a fixedelectrode 2955, 2965. The movable electrodes 2953, 2963 may move alongcircular paths defined by the cavities. The bladders 2956, 2966 may fillwith conductive or dielectric fluid. The bladders 2956, 2966 may reduceleakage of the fluid and electrically insulate the fluid from the wallsof the cavities 2950, 2960, which may allow the walls to includehigh-strength, lightweight metals. Variations in the resistance and/orcapacitance between the movable electrodes 2953, 2963 and the fixedelectrodes 2955, 2965 may be measured to determine the distance betweenthe electrodes 2953, 2955, 2963, 2965 in the manner discussed above.

Because the piston and piston shafts 2952, 2962 may rotate relative tothe bladder end cap 2954, 2964, the distance may be converted to anangle of the center shaft 2930 relative to the outer shafts 2910, 2920and/or an angle of a skeletal component coupled to the center shaft 2930relative to a skeletal component coupled to the outer shafts 2910, 2920with a vertex at the cylindrical coupling 2940 (e.g., an angulardisplacement). The angle may be expressed in units of radians, gradians,degrees, minutes of degrees, and/or the like. Displacement measuringcells may be configured to measure displacement linearly, rotationally,and/or along any curve or shape with any desired units of measurement.FIG. 29F depicts front, top, and bottom views of the radial actuator.The bladders 2956, 2966 are shown in the fully extended position forclarity. During actual use, one bladder 2956, 2966 may be fully closedwhile the other is fully opened. For example, in this embodiment, thebladder 2966 may be fully opened, and the bladder 2956 may be fullyclosed. In the fully opened position, the sensor electrodes 2953, 2955,2963, 2965 may be furthest apart, and in the fully closed position, thesensor electrodes 2953, 2955, 2963, 2965 may be closest together. Thedisplacement between the electrodes 2953, 2955 in the retraction chamber2950 may increase as the angle between the center and outer shafts 2910,2920, 2930 decreases, whereas the displacement between the electrodes2963, 2965 in the extension chamber 2960 may decrease as the anglebetween the center and outer shafts 2910, 2920, 2930 decreases. Aprocessor (not shown) may compute the angle between the center and outershafts 2910, 2920, 2930 from the electrical property measurements andmay account for the different displacement-angle relationships in eachcavity 2950, 2960. The processor may also reconcile the angles computedfrom the measurements in each cavity, such as by averaging the resultsor the like.

A calibration process similar to steps 902 to 906 of method 900 may beused to calibrate the angle measurements; Electrical propertymeasurements from the maximum extension, minimum extension, maximumretraction, and/or minimum retraction positions may be compared withstored maximum and minimum joint angles and/or measured maximum andminimum joint angles to calibrate electrical property measurements fromthe rotational hydraulic joint. The computed angles for one or morejoints may allow the processor to accurately determine the positionand/or location of one or more grippers, one or more skeletalcomponents, the limbs of the robot, hands, feet, and/or an object beinggripped using trigonometry. The computed angles may allow the geometryof an object being gripped to be determined, and/or may enhance controlover movements of the robot.

FIGS. 29C and 29D are front perspective views of the piston 2952 and theend cap 2954 that may be used in a rotational hydraulic joint. Thepiston 2952 and end cap 2954 may each include a bladder interface 2952b, 2954 b configured to couple to the bladder 2956. A plurality of ports2952 a, 2954 a may be configured to add and/or remove fluid from thebladder 2956, to electrically couple to displacement sensor electrodes2952 e, 2954 e, and/or to transfer power and/or data. In an embodiment,only the piston 2952 or only the end cap 2954 may have ports 2952 a,2954 a. The piston 2952 may include a piston head 2952 c and a pistonrod/shaft 2952 d. The electrodes 2952 e, 2954 e may be located in thepiston rod bladder interface 2952 b and/or end cap bladder interface2954 b. Lead wires may extend from the electrodes 2952 e, 2954 e intothe piston 2952 and end cap 2954. The lead wires may be insert injectionmolded into the end caps 2954, 2964 and/or piston rods 2952, 2962. As aresult, fluid may not be able to leak along the lead wires. The bladders2956, 2966, pistons 2952, 2962, and end caps 2954, 2964, may completelyseal the fluid without the use of O-rings and may eliminate thepossibility of leaking under normal circumstances.

FIGS. 29C-29F are cross-section views of the center and outer shafts2910, 2920, 2930 and the rotational hydraulic joint 2900 assembledtherefrom. The center shaft 2930 and each outer shaft 2910, 2920 may bemanufactured separately as shown in FIGS. 29C-29E. The outer shafts2910, 2920 may each include half of a cavity 2950 a, 2960 a, and thecenter shaft may include the opposing half of each cavity 2950 b, 2960b. The half cavities 2950 a,b, 2960 a,b in each shaft 2910, 2920, 2930may have the same radius. The outer shafts 2910, 2920 may contain thebladder end caps 2954, 2964, and the center shaft may contain thepistons 2952, 2962. The bladders 2956, 2966 may be inserted, and thecenter and outer shafts 2910, 2920, 2930 may be coupled together to formthe rotational hydraulic joint 2900 as shown in FIG. 29F. The pin 2945may attach the center and outer shafts 2910, 2920, 2930 together.

FIGS. 30A and 30B are cross-section views of additional rotationalhydraulic joint embodiments 3000 a-d. More joints and additionalbackground on fluid dynamics are disclosed in Fluid Power Ebook Edition1 and Fluid Power Ebook Edition 2 by Bud Trinkel, which are herebyincorporated by reference herein in their entirety. A first rotaryhydraulic joint embodiment 3000 a may include a single vane 3035 a, anda second rotary hydraulic joint embodiment 3000 b may include a doublevane 3035 b. Clockwise and counterclockwise ports 3011 a,b, 3012 a,b mayallow injected fluid to rotate the vanes 3035 a,b clockwise andcounterclockwise. The vanes 3035 a,b may be coupled to a center pin 3045a,b and may cause the center pin 3045 a,b to rotate concomitantly withthe vanes 3035 a,b. The rotating center pin 3045 a,b may cause one ormore shafts (not shown) coupled to the center pin 3045 a,b to rotaterelative to one or more shafts (not shown) coupled to a housing 3010a,b.

One or more movable electrodes 3031 a,b, 3032 a,b, 3033 b, 3034 b may beaffixed to the vanes 3035 a,b, and one or more stationary electrodes3021 a,b, 3022 a,b, 3023 b, 3024 b may be affixed to chamber dividers3025 a,b. The electrodes 3021 a,b, 3022 a,b, 3023 b, 3024 b, 3031 a,b,3032 a,b, 3033 b, 3034 b may be used to determine the angle of theshafts coupled to the center pin 3045 a,b relative to the shafts coupledto the housing 3010 a,b.

A third rotary hydraulic joint embodiment 3000 c may include a rack 3042c and pinion gear 3044 c coupled to a center pin 3045 c. A fourth rotaryhydraulic joint embodiment 3000 d may include a non-rotating piston 3042d and a spiral shaft 3045 d. Inlets 3011 c,d, 3012 c,d may allowinjected fluid to cause the rack 3042 c and/or the non-rotating piston3042 d to move laterally. The pinion gear 3044 c and the spiral shaft3045 d may translate the lateral movement of the rack 3042 c and thenon-rotating piston 3042 d respectively into rotational motion. Thecenter pin 3045 c and/or the spiral shaft 3045 d may rotate one or moreshafts (not shown) coupled to the center pin 3045 c and/or the spiralshaft 3045 d relative to one or more shafts (not shown) coupled to ahousing 3010 c,d. Stationary and movable electrodes 3021 c,d, 3022 c,d,3023 c,d, 3024 c,d, 3031 c,d, 3032 c,d, 3033 d, 3034 d may be used todetermine the angle of the shafts coupled to the center pin 3045 cand/or the spiral shaft 3045 d relative to the shafts coupled to thehousing 3010 c,d.

FIG. 31 is a schematic diagram of a mechanical joint 3100 rotated by alinear hydraulic cylinder 3130. The mechanical joint 3100 may beconfigured to rotate a second sensor 3120 relative to a first sensor3110. The first and second sensors 3110, 3120 may be coupled to a pivot3140. The second sensor 3120 may be coupled to the pivot 3140 by a pairof fixed joints 3121, 3122. The first sensor 3110 may include a fixedjoint 3111 coupled to an axis of rotation 3145 for the pivot 3140. Thefirst sensor 3110 may also be coupled to the hydraulic cylinder 3130,which may be coupled to the pivot 3140 by a connecting rod 3131. Thehydraulic cylinder 3130 may apply a force to the connecting rod 3131 andmove the connecting rod 3131 longitudinally relative to the first sensor3110. The pivot 3140 may translate the longitudinal movement from theconnecting rod 3131 into rotation. The pivot 3140 may rotate the fixedjoints 3121, 3122 and therefore the second sensor 3120 about the axis ofrotation 3145. As a result, the second sensor 3120 may rotate relativeto the first sensor 3110. The hydraulic cylinder 3130 may include adisplacement measuring cell (not shown) that can be calibrated to allowa processor (not shown) to determine the angle of the second sensor 3120relative to the first sensor 3110 based on the measurement of electricalproperties.

FIG. 32 is a schematic diagram of a plurality of sensors 3210 coupled bya plurality of mechanical joints 3230 to form a robotic finger 3200. Therobotic finger 3200 may be configured to behave like a human fingerand/or may have more or fewer joints 3230 than a human finger. Themechanical joints 3230 may allow a plurality of sensor 3210 to encirclemultiple sides of an object (not shown) and grasp the object. Aprocessor (not shown) may use displacement measurements from theplurality of sensors 3210 and knowledge about the angle of eachmechanical joint 3230 to determine the geometry of the object. Multiplefingers 3200 may be used to determine the geometry more completely, suchas by interlocking about the object. For example, one finger 3200 mayform a first U-shape in the Y and Z-axes while another may form a secondU-shape in the X and Z-axes that is inverted in the Z-axis relative tothe first U-shape.

FIGS. 33A-33C are side perspective views of various configurations of arobotic finger 3300 formed from a plurality of sensors 3310 coupled by aplurality of joints 3330. The sensors 3310 may be a series of lineardisplacement measuring modules, such as the sensor module 700. In anembodiment, the sensor arrays 3310 of the robot fingers may be one-inchmodules, such as the sensor 700. The plurality of joints 3330 mayinclude rotational hydraulic joints, mechanical joints operated bylinear hydraulic cylinders, and/or the like. The joints 3330 may berotated to form desired shapes with the robotic finger 3300. In FIG.33A, all of the joints 3330 are at 0° angles resulting in a flatsurface. The robotic finger 3300 may be placed in the flat position aspart of calibration and/or before an object (not shown) is grasped. InFIG. 33B, one sensor 3310 has joints 3330 on each side of it rotated to90° angles to form a U-shape. The maximum rotation for each finger joint3330 may be 90° or may be more or less than 90°. The illustratedconfiguration may be used as part of calibration and/or may be used tograsp opposing sides of an object (not shown) and/or to determine thegeometry of the opposing sides. In other configurations, one or morejoints at 0° angles may separate the two joints at 90° angles to form awider base to the U-shape. FIG. 33C illustrates two joints 3330 at 45°angles on each side of a sensor 3310. The smaller angles may allow thefinger 3300 to grasp a larger object (not shown). Additional joints 3330may also be rotated to 45° to more completely encircle and enclose theobject. The fingers 3300 may be able to grasp an object, and the radialrobotic joints 3330 may be able to determine the grosser dimensions ofthe object through angle measuring sensors, such as the sensor 2900. Thelinear displacement sensor modules 700 may be able to give a higherresolution to the surface of a grasped object.

FIG. 34 is a front perspective view of a robotic hand 3400 comprising aplurality of fingers 3420 a-f. In the illustrated embodiment, there maybe six fingers. Alternatively, the finger 3300 may behave like atwo-finger assembly. Each finger 3420 a-f may include one or more linearsensor arrays 3410. The linear sensor arrays 3410 may include linearhydraulic actuators in series with contact sensors. The linear hydraulicactuators may include one or more linear displacement measuring cellswith pistons, and the contact sensors one or more linear displacementmeasuring cells without pistons. Each finger 3420 a-f may also, orinstead, include one or more rotational hydraulic actuators 3430configured to measure rotational displacement. The rotational hydraulicactuators 3430 may couple outer finger segment shafts 3431 to an innerfinger segment shaft 3432. In the illustrated embodiment, each finger3420 a-f is composed of four rotational hydraulic actuators 3430, andeach section contains outer finger segment shafts 3431 and an innerfinger segment shaft 3432. In some embodiments, greater than or lessthan four rotational hydraulic actuators 3430 may be used per finger3420 a-f. The fingers 3420 a-f may be connected to a palm 3440. Eachfinger 3420 a-f may be coupled to the palm 3440 by a correspondingrotational hydraulic joint 3442, which may be able to rotate thecorresponding finger 3420 a-f laterally. The palm 3440 may also includea plurality of linear sensor arrays 3441.

The linear sensor arrays 3410, 3441 and/or the rotational hydraulicactuators 3430, 3442 may include internal bladders to contain conductivehydraulic fluid and prevent leaks. The bladders may completely seal thelinear sensor arrays 3410, 3441 and the rotational hydraulic actuators3430, 3442 without the use of O-rings and eliminate leaking under normaloperating conditions. The hydraulic fluid in the linear sensor arrays3410, 3441 may have positive pressure. When contact pressure is appliedto the linear sensor arrays 3410, 3441, fluid may be forced out of thesensor arrays, and the bladders may roll up around correspondinginternal pistons. The force from the contact pressure may act like aspring to remove the fluid, roll up the bladders, and cause the linearsensor arrays 3410, 3441 to conform to the object applying the contactpressure. The conformity may allow a geographic model to be determinedfrom the displacement measurements of the linear sensor arrays 3410,3441.

The flow of fluid into and out of the linear sensor arrays 3410, 3441and/or rotational hydraulic actuators 3430, 3442 may be controlled by aplurality of control valves (not shown). In some embodiments, there maybe one or two control valves for each linear sensor array 3410, 3441and/or two control valves for each rotational hydraulic actuator 3430,3442. One control valve may control extension and another control valvemay control retraction. Alternatively, two control valves may controlall of the rotational hydraulic actuators 3430, 3442 and/or linearsensor arrays 3410, 3441, or there may be two control valves for eachfinger 3420 a-f. In an embodiment, opposing fingers (e.g., the fingers3420 a and 3420 b) may operate in a manner similar to an index fingerand thumb, and there may be common control valves for each set ofjoints. For example, a first joint in each of the two fingers may becontrolled by two control valves, and the second, third, and fourthpairs of joints would each have a pair of common control valves.Alternatively, or in addition, two pairs of the fingers 3420 a-f may becontrolled by two control valves, and one pair may behave like an indexfinger and thumb and be controlled by another two, four, or eightcontrol valves.

A pair of the fingers 3420 a-f may be able to grasp small objects and/ortools, such as tweezers. Two pairs of the fingers 3420 a-f may close,and the remaining pair may stay straight to manipulate objects. One ormore gripping algorithms may be used to control the fingers 3420 a-faccording to the type of grip desired. The gripping algorithms mayprovide for precise control when using a pair of the fingers 3420 a-f. Aseparate gripping algorithm or instance of a gripping algorithm maycontrol each pair of the fingers 3420 a-f.

The linear sensor arrays 3410, 3441 may be filled with fluid before anobject is grasped. The control valves may allow fluid to drain from thelinear sensor arrays 3410, 3441 as the object is grasped, which may onlyrequire one or two control valves per linear hydraulic actuator 3410,3441 and/or one or two control valves for a plurality of linearhydraulic actuators 3410, 3441 (e.g., one or two control valves maycontrol all draining). Pressure regulation may be used to ensure onlythe desired amount of fluid is permitted to drain. The pressure may bebalanced between drain valve switching, pressure on the contact walls tocause the bladder to roll up, and pressure on the object being gripped.The wall thickness of the bladder may also affect rolling of the bladderand/or the applied pressure.

The rotational hydraulic actuators 3430, 3442 and the linear sensorarrays 3410, 3441, including the linear hydraulic actuators and thecontact sensors, may be used to create a geographic model of an objectbeing grasped. Measurements from the rotational hydraulic actuators3430, 3442 and trigonometry may be used to create a gross model of theobject. The linear sensor arrays 3410, 3441 may be used to determinefine details of the object and create a fine model with higherresolution. There may be gaps between the linear sensor arrays 3410,3441, so several methods may be used to model the object where the gapsare. The model may be interpolated and/or extrapolated to fill in thegaps. The hand 3400 may move and/or index around the object to fill inany gaps. Because the locations of the gaps may be known, determined,and/or stored by the processor, the movements can be configured toensure a fine model of every part of the object is created.Alternatively, or in addition, two hands 3400 may be used to grip theobject and enclose the object on six or more or fewer sides. The methodof filling in gaps may depend on the particular application and whetherinterpolation and/or extrapolation is sufficient or if a model createdcompletely from measurements is required.

FIG. 35 is a front perspective view of an end cap 3520 that may becoupled to an inner core 3510. The inner core 3510 may be the male endof a skeletal component and/or joint. The end cap 3520 and inner core3510 may have threads 3515, 3525 that interface to removeably couple theend cap 3520 to the inner core 3510. The end cap 3520 may comprise afluid port 3521, an electrical power port 3522, and a data port 3523 totransfer fluid, electrical power, and data respectively to other robotcomponents. External attachments to the power ports may be used tocharge, discharge, and/or couple in series and/or parallel the batteries2520, 2530 of the skeletal system. The ports may be located on the sidesand/or the end of the end cap 3520. The ports 3521, 3522, 3523 may beself-sealing to allow for quick disconnection of the skeletal component2500 from the robot without sparking or fluid loss for batterymaintenance, repair, and replacement. Corresponding ports with which theend cap ports 3521, 3522, 3523 interface may also be self-sealing.

Alternatively or in addition, the inner core 3510 may interface with ajoint, such as the rotational hydraulic joint 2900, the rotationalhydraulic joints 3000 a-d, the mechanical joint 3100, the roboticfingers 3300, or the like, to allow for moving and orienting a skeletalcomponent 2500. The joint may include a quick release connection thatremoveably couples with a quick release system of the skeleton. Thejoint may be a prismatic, ball, screw, pin and socket, revolute joint,or the like. The joint may be a compound joint with a predeterminednumber of degrees of freedom. For example, the joint may be a hip with 3degrees of freedom; a knee with 1 degree of freedom; an ankle with 2degrees of freedom; an arm, including a shoulder, elbow, and wrist, with7 degrees of freedom; a back with a plurality of degrees of freedom; orthe like. The joint may be actuated by electric motor, hydraulic means,pneumatic means, or the like. Electrical power, data, and fluid may bepassed through the joint to reduce wiring, hoses, and cables, and/or arotary joint may be used to transfer electrical power. The inner core3510 and joint may be connected by a thread and screw, quick releaseflange, or the like. For example, the inner core 3510 may have flangeson either or both ends that connect the inner core 3510 to the joint. Aquick release connection may allow discharged batteries 2520, 2530 to bequickly replaced. Thus, panels in the robot may be opened to remove andexchange skeletal components, and/or the skin may be removed to replacethe inner skeleton battery structure. The skeleton and skin may bothhave integrated batteries, so replacement of the skin batteries createsaccess to the inner skeleton battery structure for replacement. Roboticjoints may be available from Boston Dynamics, Fanuc, Kuka, and MotomanRobotics.

FIG. 36 is a front perspective view of a skeletal component 3600 with amale end 3610 and a female end 3620. The male end 3610 may be configuredto mate with the female end 3620, which may allow multiple skeletalcomponents to be coupled to one another. The male and/or female ends3610, 3620 may also be configured to mate with female and/or malereceptacles of joints, such as the rotational hydraulic joint 2900, themechanical joint 3100, or the like. The skeletal component 3600 mayinclude an integrated battery 3630 surrounding an inner core 3640. Theintegrated battery 3630 may be cylindrically wound around the inner core3640, such as using windings 2600 a with or without additional supportbattery windings 2600 b. The female end 3620 and an output section 3660may enclose and/or bound the battery 3630 on each end to preventlongitudinal displacement of the battery 3630 relative to the inner core3640. The battery may be electrically coupled to at least one of theoutput section 3660 and the female end 3620. For example, the female end3620 may include one or more simple and/or complex switches, such asswitching power supplies, configured to switch the battery 3630 into andout of charging and discharging circuits to optimize battery and powerusage.

The female end 3620 and the output section 3660 may each includehydraulic fluid ports 3621, 3661, electrical power ports 3622, 3662,data ports 3623, 3663, and/or the like. Fluid, electrical power, and/ordata may be transferred from the female end 3620 to the output section3660 and/or from the output section 3660 to the female end 3620. Thefluid ports 3621, 3661 may be divided into two sections. One section maytransfer fluid to and/or from one or more extension chambers (e.g.,extension chamber 692 and/or extension cavity 2960) in one or moregrippers, joints, and/or skeletal components, and the other section maytransfer fluid to and/or from one or more retraction chambers (e.g.,retraction chamber 694 and/or retraction cavity 2950) in one or moregrippers, joints, and/or skeletal components. Alternatively, the femaleend 3620 and output section 3660 may each have two fluid ports (notshown); one fluid port may be for extension and one may be forretraction. In an embodiment, the female end 3620 may receive fluid froma pump directly or indirectly (e.g., the fluid port 3623 may be in fluidcommunication with the pump), and the output section 3660 may transferthe fluid to other components directly or indirectly.

Alternatively, or in addition, fluid, electrical power, and/or data maybe transferred by the inner core 3640. The inner core 3640 may transferfluid, electrical power, and/or data to a joint, to other skeletalcomponents, and/or to other robotic systems. A plurality ofnon-interconnected fluid chambers 3641, 3642 may transport fluidlongitudinally through the center of the inner core 3640. A firstchamber 3641 may transfer fluid to and/or from one or more extensionchambers and a second chamber 3642 may transfer fluid to and/or from oneor more retraction chambers. Each chamber 3641, 3642 may include aninsulator sleeve (not shown) configured to insulate the conductive fluidfrom the inner core 3640. The insulator sleeve may divide the cavity inthe inner core 3640 into the two chambers 3641, 3642. In an embodiment,the first and second chambers 3641, 3642 may deliver fluid to a joint(not shown) connected directly to the skeletal component 3600, and theoutput section fluid port 3661 may deliver fluid to joints and skeletalcomponents further away (not shown). In other embodiments, the first andsecond chambers 3641, 3642 may deliver fluid to both directly connectedand further away joints and skeletal components.

The inner core 3640 may include one or more highly conductive surfaceelements 3643, 3644 extending longitudinally along the outside of theinner core 3640. The highly conductive surface elements 3643, 3644 maycomprise silver, gold, copper, aluminum, and/or the like. One or moresurface elements 3643 may transfer electrical power, and one or moresurface elements 3644 may transfer data. Alternatively, or in addition,the surface elements 3643, 3644 may be a thin film divided into aplurality of transfer lines. The electrical power transferred by thesurface elements 3643 may be used to charge and/or discharge batteries3630 in the skeletal component 3600 or in other skeletal components (notshown) and/or to power devices and components throughout a robot (notshown). The power transfer lines may be sized based on the expectedelectrical current requirements. The number of data lines may correspondto the requirements for communication between the joints, hands, feet,and the like with a controller and/or a PLC. Some joints may not need ortransfer electrical power or data, so an insulator (not shown) may coverthe surface elements 3643, 3644 at the male end 3610 in someembodiments. A core cylinder 3645 may provide form and strength to theinner core 3640. The core cylinder 3645 may be made from ahigh-strength, lightweight material, such as titanium, aluminum, carbonfiber, and/or the like. Insulators 3646, 3647 may electrically insulatethe core cylinder 3645 from the fluid chambers 3641, 3642 and/or surfaceelements 3643, 3644 to prevent undesirable short circuits that mightotherwise result. The fluid chambers 3641, 3642 and surface elements3643, 3644 may be coupled to the ports 3621, 3622, 3623, 3661, 3662,3663 of the female end 3620 and/or output section 3660.

FIG. 37 is a schematic diagram of a compound ball joint 3700 with threedegrees of freedom. The compound ball joint 3700 may include threeconstituent joints 3710, 3720, 3730, each having a single degree offreedom. More or fewer constituent joints 3710, 3720, 3730 may beincluded in other embodiments. Each constituent joint 3710, 3720, 3730may be configured to rotate in a different orthogonal plane. Forexample, in the illustrated embodiment, a first constituent joint 3710may rotate in the XZ plane, a second constituent joint 3720 may rotatein the YZ plane, and a third constituent joint 3730 may rotate in the XYplane. The constituent joints 3710, 3720, 3730 may each include asemicircular cavity through which a piston 3722 rotates. The constituentjoints 3710, 3720, 3730 may each comprise the rotational hydraulic joint2900. The constituent joints 3710, 3720, 3730 may be connected togetherby second and third piston shafts 3724, 3734. The third joint 3730 mayrotate the first and second joints 3710, 3720, and the second joint 3720may rotate the first joint 3710. Thus, a first skeletal component 3761coupled to the first piston shaft 3714 may be rotated in one or more ofthe three orthogonal planes by the constituent joints 3710, 3720, 3730.Each constituent joint 3710, 3720, 3730 may include a measuring cell,such as the measuring cell in the rotational hydraulic joint 2900, todetermine the angle of rotation of the constituent joint 3710, 3720,3730. A processor (not shown) may compute the position of the firstskeletal component 3761 using trigonometry.

In an embodiment, the constituent joints 3710, 3720, 3730 includesemicircular cavities and the piston shafts 3714, 3724, 3734 are alsosemicircular with a similar radius to allow the pistons 3722 to traversethe semicircular cavities. Each constituent joint 3710, 3720, 3730 mayallow a maximum rotation of 90°, 135°, 180°, 225°, 240°, 270°, 360°,and/or the like. The pistons 3722 may or may not have one or more setsof ball bearings (not shown) to facilitate movement along thesemicircular cavity. Also, a ring of ball bearings (not shown) may be incontact with the shaft 3714, 3724, 3734 where the shaft 3714, 3724, 3734exits the semicircular cavity. The ball bearings may reduce stress onthe piston 3722 movements and/or increase the amount of weight that maybe applied to the piston 3722. A single semicircular cavity may be usedfor both retraction and extension. The constituent joints 3710, 3720,3730 may include two end caps (not shown) coupled to each piston 3722 bytwo bellow bladders (not shown). The bellow bladder through which thepiston shaft 3714, 3724, 3734 travels may surround the piston shaft3714, 3724, 3734 to prevent leaking. In other embodiments, theconstituent joints 3710, 3720, 3730 may include the rotational hydraulicjoint 2900, the mechanical joint 3100, or the like.

A control module 3740 may be configured to adjust the position of theconstituent joints 3710, 3720, 3730. The control module 3740 may includesix control valves (not shown). A pump (not shown) may apply positivepressure to a fluid, and the control valves may direct the fluid to oneor more desired locations for movement of the constituent joints 3710,3720, 3730. One control valve for each joint may control filling anddraining of the extension chamber, and one control valve for each jointmay control filling and draining of the retraction chamber. In otherembodiments, there may be two control valves per chamber of each jointto control fluid flow into and out of the chambers. The control valvesmay be coupled to the constituent joints 3710, 3720, 3730 by hoses (notshown) and/or through a first control module connector 3741. In otherembodiments, the control valves may be located in the joints that theycontrol. The processor and/or a PLC may signal to the control module3740, which valves to open and which to close. The control module 3740may also include a multiplexer configured to multiplex together thesignals and/or electrical property measurements from each joint.

Male and female housing components 3751, 3752 may house the constituentjoints 3710, 3720, 3730 and may leave only the control module 3740 and afirst skeletal component 3761 exposed for external connection. The malehousing component 3751 may be coupled to the control module 3740, andthe female housing component 3752 may be coupled to the firstconstituent joint 3710. A second control module connector 3742 and thefirst piston shaft 3714 may emerge from the housing to couple thecompound ball joint 3700 to skeletal components 3761, 3762. The secondcontrol module connector 3742 may be the male end of the second skeletalcomponent 3762, and a flange (not shown) may couple the second controlmodule connector 3742 to the control module 3740. The skeletalcomponents 3761, 3762 may or may not include integrated batteries and/ormay be fingers or finger joints. Fluid, electrical power, and/or datamay be delivered to the compound ball joint 3700 from the skeletalcomponents 3761, 3762 and/or vice versa.

FIG. 38 includes top, front, and side perspective views of a compact,compound joint 3800. The compact, compound joint 3800 may include threeconstituent joints 3810, 3820, 3830, each having a single degree offreedom. More or fewer constituent joints 3810, 3820, 3830, such as onlytwo constituent joints 3810, 3820, may be included in other embodiments.The constituent joints 3810, 3820, 3830 may have a configuration similarto that of the constituent joints 3710, 3720, 3730 in the compound balljoint 3700 and/or may include rotational hydraulic joints 2900,mechanical joints 3100, and/or the like. Each constituent joint 3810,3820, 3830 may be configured to rotate in a different orthogonal plane.The constituent joints 3810, 3820, 3830 may be closer to each other thanthe constituent joints 3710, 3720, 3730 in the compound ball joint 3700to reduce the volume of the compact, compound joint 3800. For example,each constituent joint 3810, 3820, 3830 may be positioned with at leastone portion near the center of one or more adjacent constituent joints3810, 3820, 3830. Piston shafts 3815, 3825, 3835 may couple theconstituent joints 3810, 3820, 3830 together. The piston shafts 3815,3825, 3835 may be coupled to adjacent constituent joints 3810, 3820,3830 near their center.

FIG. 39 is a schematic diagram of an arm 3900 including a plurality ofcompound joints 3910 a-c with multiple degrees of a freedom and aplurality of skeletal components 3920 a-c. The joints 3910 a-c andskeletal components 3920 a-c may include male and female connectionsthat may interface with one another. Flanges, fittings, or the like mayalso or instead be used to attach the joints 3910 a-c and skeletalcomponents 3920 a-c. The arm 3900 may be part of a larger skeletalsystem for a robot. For example, a spinal joint 3915 may couple a head(not shown), another arm (not shown), additional spine joints (notshown) coupled to a waist (not shown) and/or legs (not shown), and/orthe like to a proximal end of the arm 3900. The arm 3900 may include orcouple to a hand 3925 or other gripper at a distal end, such as the hand3400. The arm 3900 may be configured to have a functionality similar tothat of a human arm. Accordingly, a shoulder joint 3910 a may have threedegrees of freedom, an elbow joint 3910 b may have one degree offreedom, and a wrist joint 3910 c may have two degrees of freedom. Thoseof skill in the art will understand the joints 3910 a-c may have more orfewer degrees of freedom depending on the desired application of the arm3900.

The arm 3900 may be configured to transfer fluid, electrical power,data, and/or the like to components of the arm 3900 and/or componentsoutside the arm 3900. The fluid, electrical power, and data may beconveyed by the joints 3910 a-c and skeletal components 3920 a-c.Transfer lines, such as wires 3932 a-c, 3933 a-c, hoses 3931 a-c, or thelike, may transfer fluid, electrical power, and/or data between skeletalcomponents 3920 a-c instead of or in addition to the joints 3910 a-c.Some embodiments may not include transfer lines apart from the joints3910 a-c and skeletal components 3920 a-c and may instead transferfluid, electrical power, and/or data through the joints 3910 a-c and/orskeletal components 3920 a-c.

The skeletal components 3920 a-c may include one or more control modules3921 a-c, 3922 a-c. The skeletal components 3920 a-c may each include aplurality of batteries (not shown) that have their charging regulatedand/or controlled by a first control module 3921 a-c in each skeletalcomponent 3920 a-c. The first control modules 3921 a-c may includeand/or be communicatively coupled with temperature, pressure, and/orvoltage sensors that monitor the temperature, pressure, and/or voltageof the batteries. The first control modules 3921 a-c may also includecontrol mechanisms and/or circuitry configured to regulate charging anddischarging of the batteries. The first control modules 3921 a-c maymonitor and control a charge profile for the batteries by switching acharging current. An exemplary charge profile is disclosed in U.S. Pat.No. 5,633,576 to Rose et al., which is hereby incorporated herein byreference in its entirety. The first control modules 3921 a-c maymonitor and control the voltage of each battery as a function ofmeasured temperature, pressure, charging voltage, discharging voltage,and/or the like.

A second control module 3922 a-c in each skeletal component 3920 a-c maytransfer fluid, electrical power, and/or data to the joints 3910 a-cand/or the hand 3925. In some embodiments, only fluid and data may beoutput to the joints 3910 a-c. The joints 3910 a-c may include a jointcontrol module, such as the control module 3740, inside the jointhousing. The joint control module may include a plurality of valves tocontrol extension and retraction of the joints 3910 a-c in one or moredegrees of freedom in the manner previously discussed. A plurality ofjoint connections 3911 a-c, 3912 a-c may convey fluid, electrical power,and/or data between the joints 3910 a-c and the skeletal components 3920a-c and/or the hand 3925. In some embodiments, second joint connections3912 a-c may only provide a mechanical connection and may not transferfluid, electrical power, and/or data. First joint connections 3911 a-cfor each joint 3910 a-c may be comprised of a male receptacle from theskeletal component 3920 a-c and a female receptacle from the joint 3910a-c, which may interface to transfer fluid, electrical power, and/ordata between the skeletal component 3920 a-c and the joint 3910 a-c.

FIG. 40 is a schematic diagram of a robotic foot 4000 configured toprovide mobility and balance. The robotic foot 4000 may be connected toa robot skeletal component 4060 by an ankle ball joint 4030. Amechanical connection 4031 may couple the ankle ball joint 4030 to thefoot 4000. The foot 4000 may include a plurality of sensors 4010, 4012,4020 that can be used to determine balance. A support element 4040,stabilizers 4025, and a housing 4044 may provide structure and stabilityto the foot 4000. The support element 4040 may comprise a hard material,such as thermoplastic or metal.

The ankle ball joint 4030 may be configured to have two, three, or moreor fewer degrees of freedom. The ankle ball joint 4030 may include oneor more rotational hydraulic joints (not shown) configured to controlmovement of the foot 4000 and/or measure the angle of the foot 4000relative to the robot skeletal component 4060. A processor (not shown)may control movement of the ankle ball joint 4030 to maintain balancebased on feedback from the sensors 4010, 4012, 4020, measurements of theangle of the ankle joint 4030, measurements of the angles of otherjoints (not shown), and/or measurements and/or determinations of thespeed of movement. In an embodiment, the foot 4000 may walk using arolling effect similar to the rolling from heel to toe of a human footduring walking/running. The foot 4000 may be symmetrical and able toroll forward and backward or in three or four possible directions,and/or the foot 4000 may be unsymmetrical and only able to roll in onedirection.

The foot 4000 may comprise a plurality of hydraulic linear displacementsensors 4010, 4012 in contact with the bottom of the foot 4000. In someembodiments, the linear displacement sensors 4010, 4012 may includehydraulic cylinders with pistons and not include hydraulic cylinderswithout pistons, because the foot 4000 may require less perpendicularresolution and higher resilience to strong forces. The lineardisplacement sensors may be configured with components able to withstandthe higher pressures that may result from supporting the weight of arobot. In an embodiment, each linear displacement sensor 4010, 4012 mayhave a contact surface area of 1 square inch, and there may be a 12 by 4array of linear displacement sensors 4010, 4012. Fewer lineardisplacement sensors 4010, 4012 may be suitable in other embodiments.

The linear displacement sensors 4010, 4012 may be configured to measurethe contour of the ground and/or to measure the pressure on each sensor4010, 4012. The contour and/or pressure measurements may be sent to theprocessor for use in determining weight shifting, weight distribution,and/or the like to maintain balance. A geographic contour map may becomputed from displacement measurements by the linear displacementsensors 4010, 4012. The linear displacement sensors 4010, 4012 may beconfigured to detect rolling, shifting, and/or moving objects under thefoot 4000 (e.g., when the foot 4000 is standing on marbles). Pressuresensors may be used to determine the pressure in each of the lineardisplacement sensors 4010, 4012, and/or the pressure may be determinedfrom the displacement of each piston. Absolute and/or relative pressuresmay be computed. A robot may be loaded with a weight. The displacementof the linear displacement sensors 4010, 4012 may be load dependent fora given hydraulic line pressure, and the weight or mass of the load maybe determined by the displacement of the sensors in the lineardisplacement sensors 4010, 4012. The load may be determined by knowingthe weight of the robot, and the amount of pressure needed to linearlydisplace the pistons in the linear displacement sensors 4010, 4012. Insome embodiments, the total weight of the robot including any load maybe used to determine the pressure. The displacement-to-pressurecalculation may be calibrated with any changes in load, and/or changesin load may be detected by the linear displacement sensors 4010, 4012.Angled linear displacement sensors 4012 may included angled endeffectors and may detect ground contour, pressure, and/or shear forcesas the foot 4000 leaves or touches the ground during rolling.

The linear displacement sensors 4010, 4012 may be able to level or alterthe angle of the foot 4000 and/or conform the foot 4000 to the ground byregulating the pressure of fluid in each of the linear displacementsensors 4010, 4012. In an embodiment, the pressures may be equalized.The pressure in the linear displacement sensors 4010, 4012 may becontrolled in response to the changing contact area during walking, suchas when the foot 4000 is rolled during walking. The foot 4000 mayinclude one or more pressure control valves (not shown) configured toregulate the pressure of each linear displacement sensor 4010, 4012. Thepressure control valves may regulate the pressure with respect to thetotal weight of the robot and/or any load carried. The pressure controlvalves may regulate the pressure based on a known load.

The foot 4000 may comprise one or more shear sensors 4020. The shearsensors may be located between one or more of the linear displacementsensors 4010, 4012. The shear sensors 4020 may be coupled to the supportelement 4040 by stabilizers 4025. The shear sensors 4020 may be used todetermine the coefficient of friction between the foot 4000 and theground. The coefficient of friction may be computed based on thepressure, total weight, angle, and/or shear force experienced by thefoot 4000. The processor may use the determined coefficient of frictionto improve mobility and/or balance on surfaces with differentcoefficients of friction. For example, a plurality of walking algorithmsmay be stored, and one or more appropriate walking algorithm may beselected based on the determined coefficient of friction. Alternatively,the parameters of one or more walking algorithms may be changed based onthe determined coefficient of friction. The walking algorithms maycontrol movement of the linear displacement sensors 4010, 4012 and/orankle ball joint 4030. Measurements on a plurality of dry and/or wetsurfaces, such as ice, sand, dirt, concrete, etc., may be used forcalibration. The shear sensors 4020 may be configured to measure shearfrom when the foot 4000 first touches the ground until the foot 4000leaves the ground even if the foot 4000 is rolled. Exemplary shearsensors may include piezoresistive sensors, PVDF sensors, and/or thelike. The shear sensors 4020 may include cantilevers configured to beperpendicular to the ground as the foot rotates.

The housing 4044 may be an elastic sheet comprising thermoplastic, anelastomer, such as rubber, or the like. The housing 4044 may beconfigured to have a large coefficient of friction with certain and/ormost materials, and/or the housing 4044 may include texture and/orroughness configured to increase traction. In some embodiments, the foot4000 and/or the housing 4044 may include a plurality of pressure sensorsinstead of or in addition to the linear displacement sensors 4010, 4012.The pressure sensors may be used to determine a weight and/or pressuredistribution pattern. An array of pressure sensors may be able todetermine the scalar differences of the distribution of pressure. Thepressure sensors, shear sensors 4020, and/or linear displacement sensors4010, 4012 may be insert molded into the housing 4044.

FIGS. 41A and 41B are a flow diagram of a method 4100 for walking usingthe robotic foot 4000. Various configurations of the robotic foot 4000may be used with the method 4100 for walking. In an embodiment, the flatsection of the robotic foot 4000 may include an 8 by 4 array of lineardisplacement sensors 4010 and heel and toe sections of the robotic foot4000 may each include 2 by 4 array of linear displacement sensors 4012.The linear displacement sensors 4010, 4012 may be configured to act ashydraulic actuators and may each have a surface area of 1 square inch.The shear sensors 4020 may be located between the linear displacementsensors 4010, 4012 as needed. A hydraulic pump may output a pressure of30 psi. Higher pressures may be used in some embodiments depending onthe application. A robot supported by the robotic foot 4000 may be 150lbs. with a maximum load of 80 lbs. The hydraulic fluid may bedistributed and/or controlled by servo control valves. The heel, toe,and flat section may each have a single separate servo control valvethat controls the corresponding section in common. A separate algorithmmay be used to control the ankle joint 4030. The separate anklealgorithm may allow the ankle 4030 to angle the foot to conform to adesired surface, and/or a maximum tilt angle may be programmed into theprocessor. The ankle 4030 may be configured to enable higher force onspecific portions of the foot's linear displacement sensors 4010, 4012.Ankle shifting may be detected on shifting surfaces, such as rocks, whenthe weight is shifted from one foot to the other, and weightdistribution can be adjusted to correspond to surface stability.

The method 4100 may begin with initial calibration 4102 of the robot andload. Calibration may include mapping electrical property measurementsfor maximum and minimum extension positions to displacements,determining the weight of the robot and/or load, and/or the like. Whenwalking begins, the robotic foot 4000 may be lifted from the ground, andall the linear displacement sensors 4010, 4012 may be expanded 4104 tothe maximum extension position and filled with fluid. The robotic foot4000 may return to the ground heel first. As the heel touches theground, the force from the contact may push fluid out of the lineardisplacement sensors 4012 in the heel. A processor may detect that thelinear displacement sensors 4012 are contracting and activate servovalves to increase 4106 pressure in and add fluid to the lineardisplacement sensors 4012 in the heel. From measurements by the lineardisplacement sensors 4012 in the heel, the processor may calculate 4108the angle of the slope of the ground.

The processor and servo control valves may maintain 4110 the lineardisplacement sensors 4012 at a level of half-full based on themeasurements from the linear displacement sensors 4012. The level of thefluid within the linear displacement sensors 4012 may be averaged, andthe average level may be maintained at half-full. The processor maycalculate 4112 the angle of the robotic foot 4000. Based on thecalculations, the robotic foot may be leveled 4114 by actuating thelinear displacement sensors 4012. The processor may calculate 4116 thepressure distribution and/or the load attributed to each lineardisplacement sensor 4012. The load attributed to each lineardisplacement sensor may be calculated from the foot angle, hydraulicfluid pressure in the linear displacement sensors 4012 of the heel,displacement measured by the linear displacement sensors 4012, totalrobot weight, and/or the like. The shear force (e.g., deflection ofcantilevers within the shear sensors 4020) may be measured 4118. Amaximum velocity for shifting weight between feet may be calculated 4120based on the shear force, estimated load, ground slope, weightdistribution, foot angle, and/or the like. A coefficient of friction maybe estimated 4122 from the total weight, velocity, pressuredistribution, shear force, and/or the like.

As the flat section of the foot touches the ground, the processor maycalculate 4124 the angle of the robotic foot 4000. The processor maymeasure 4126 piston displacement in the linear displacement sensors 4010in the flat section of the robotic foot 4000. If some of the lineardisplacement sensors 4010 do not move during contact, the lack ofmovement may indicate that those linear displacement sensors 4010 arenot touching the ground and/or bearing weight. Fluid may be pumped 4128into the linear displacement sensors 4010 to level the robotic foot4000. The processor may fill 4130 the linear displacement sensors 4010to half-full. The processor may attempt to make all the lineardisplacement sensors 4010 half-full. If it is not possible to make allthe linear displacement sensors 4010 half-full, the processor may settlewith the average fluid height for the linear displacement sensors 4010being half-full. Filling 4130 the linear displacement sensors 4010 maycomprise increasing the pressure in the linear displacement sensors 4010until the linear displacement sensors 4010 are distributed from maximumto minimum. In some embodiments, the pressure may be increased in onlylinear displacement sensors 4010 making contact with the ground.

The processor may calculate 4132 the geography of the ground surfacefrom linear displacement measurements by the linear displacement sensors4010. A pressure distribution profile may be used to level 4134 the loadamong the linear displacement sensors 4010 and minimize the angle of therobotic foot 4000. The processor may calculate 4136 the angle of therobotic foot 4000 necessary to lift the foot off the ground when rollingthe foot from heel to toe. The angle may be calculated 4136 while theankle joint 4030 rotates and the leg lifts to remove the heel and flatsection of the robotic foot 4000 off the ground. The robotic foot 4000may be held at an angle that maximizes pressure distribution on the toesection. The maximum velocity of the foot 4000, knee, and/or hipsections are calculated 4138 from the shear force, estimated coefficientof friction, pressure distribution, total weight, ground slope, and/orthe like. The body may be tilted 4140 to correspond to the maximumvelocity of the hip and/or the slope of the ground.

The linear displacement sensors 4012 in the toe may be filled 4142 to anaverage of half-full as the toe rotates, lifts, and pushes from theground based on displacement measurements by the linear displacementsensors 4012. The processor may attempt to make the average fluid heighthalf-full and as many of the linear displacement sensors 4012 half-fullas possible. The shear force and/or pressure distribution may bemeasured 4144. The velocity may be controlled 4146 based on the shearforce detected and/or the weight measurement. The maximum possiblevelocity may be directly proportional to the shear force detected with ahigher shear force allowing for a faster possible velocity. The weightmay be monitored 4148 for changes in distribution and/or load.

The total weight of the robot and load may be calculated from thepressure distribution of the linear displacement sensors 4010, 4012, thepressure output from the servo control valves, and/or the cumulativedeflection of the pistons of the linear displacement sensors 4010, 4012when all the weight is on one foot. The calculated value for totalweight may be carried over from the previous step if no change isdetected, and/or the weight may be detected with each step from thelinear displacement sensor 4010, 4012 measurements and/or the hydraulicvalve pressure necessary to elevate the foot as a load is lifted. Thevalues for weight and coefficient of friction may be estimated as theheel touches the ground, as the flat section touches the ground, and/oras the toe leaves the ground. An initial estimated weight and/or massmay be determined from the weight of the robot without load. The weightof the robot without load may be input into and/or stored by the robot.The maximum velocity, acceleration, and/or deceleration may becalculated from the momentum (mass times velocity) of the robot, theestimated coefficient of friction between the foot and the groundsurface, and/or the like. The maximum acceleration and/or decelerationmay be the maximum change in velocity that will not cause the roboticfoot 4000 to slip. If a loss of traction and/or slipping is detected, anew coefficient of friction may be calculated based on the amount offorce being applied when the slipping occurred. The shear sensors 4020,linear displacement sensors 4010, 4012, displacement sensors in theankle 4030, knee, and/or hip, and/or the like can be monitored to detectslipping. The processor may closely monitor slippage as a variable usedwhen calculating the coefficient of friction.

It may be advantageous to keep a relatively low applied pressure to thelinear displacement sensors 4010, 4012 before contact is made with theground and increase the pressure as contact is made with the ground.Continuous feedback from the linear displacement sensors 4010, 4012, theshear sensors 4020, and/or the servo control valves may allow theprocessor to make instantaneous adjustments to the pressure in thelinear displacement sensors as various changes in conditions aredetected, such as a change in the perceived weight. The lineardisplacement sensors 4010, 4012 may be calibrated for weight as afunction of servo control valve pressure regulation.

FIG. 42 is a schematic diagram of a complete skeleton system 4200 for arobot. The skeleton system 4200 may include a plurality of compoundjoints (e.g. joints 4210 a-c, 4220 a-c, 4230 a-c) connected together byskeleton sections (e.g., skeleton sections 4240 a, 4240 b) including oneor more skeletal components, each of which may or may not includebatteries. The plurality of joints may be configured to move in a mannersimilar to human joints. For example, a shoulder joint 4210 a may havethree degrees of freedom, a elbow joint 4210 b may have one degree offreedom, a wrist joint 4210 c may have two degrees of freedom, a neckjoint 4220 a may have two degrees of freedom, a spinal column joint 4220b may have one or two degrees of freedom, a waist joint 4220 c may havetwo degrees of freedom, a hip joint 4230 a may have three degrees offreedom, a knee joint 4230 b may have one degree of freedom, and anankle 4230 c joint may have two degrees of freedom. More or fewerdegrees of freedom may be included in some embodiments. Hands 4250 andfeet 4260 may be coupled to the skeleton 4200 by mechanical connections(e.g., mechanical connections 4251, 4261).

The skeleton system 4200 may include a head 4270. The head 4270 may becoupled to the skeleton system 4200 by a joint (not shown) with twodegrees of freedom. The head 4270 may include vision systems, audiosystems, various sensory systems, and/or the like. Examples of sensorysystems may include gyroscopes, stereo cameras, sonic sensors, LIDAR,optical sensors, and the like. The skeleton system 4200 may also includea central hydraulic pumping system (not shown) and reservoir (notshown). One pump may be configured to deliver fluid to all of the joints4210 a-c, 4220 a-c, 4230 a-c; one pump may be used for each limb 4210,4230; and/or the skeleton system 4200 may include more or fewer than onepump or one pump per limb. In an embodiment, the hydraulic pumpingsystem and reservoir are located in a torso and/or body of the robot.The joint motions may be controlled by hydraulic valves for each jointindividually with a central hydraulic pump. The pump may supply apositive pressure to the hydraulic valves.

Each compound joint 4210 a-c, 4220 a-c, 4230 a-c may contain one or moreflow meters, and/or each constituent joint within the compound joints4210 a-c, 4220 a-c, 4230 a-c may contain or be coupled to one or moreflow meters. Each pump and/or reservoir (not shown) may also includeflow meters. By monitoring the total flow of fluid through each joint4210 a-c, 4220 a-c, 4230 a-c, leaks may be detected. The flow of fluidinto each joint 4210 a-c, 4220 a-c, 4230 a-c may be compared with theflow of fluid out of each joint 4210 a-c, 4220 a-c, 4230 a-c, and/or thetotal flow out of the pump and/or reservoir may be compared with thetotal flow through all the joints 4210 a-c, 4220 a-c, 4230 a-c. If it isdetermined that the hydraulic system is leaking, the hydraulic systemand/or components of the hydraulic system may be deactivated. Grippersand/or the skeletal components 4240 a, 4240 b may also include flowmeters to detect leaks.

One or more processors (not shown) may send signals to control valvesfor each joint 4210 a-c, 4220 a-c, 4230 a-c to control movement of eachjoint 4210 a-c, 4220 a-c, 4230 a-c, the hands 4250, and the feet 4260.In an embodiment, different processors may perform different functions,such as one processor implementing a walking algorithm and anotherimplementing a gripping algorithm, and/or one or more processors mayinclude multiple cores configured to perform different functions and/orto process different threads. The one or more processors may receivemeasurements from joint measurement cells to determine the locations ofthe limbs 4210, 4230, the hands 4250, and/or the feet 4260 and/oridentify objects in hands 4250 and/or grippers. The one or moreprocessors may be located in the head 4270, torso, body, or the likeand/or may be distributed throughout the robot 4200 based on function.The skeleton system may include a power inlet for receiving electricalpower and battery charging and discharging hardware and/or software. Theinlet, hardware, and/or software may be located in the head 4270, torso,body, or the like.

It will be understood by those having skill in the art that many changesmay be made to the details of the above-described embodiments withoutdeparting from the underlying principles of the disclosure. For example,components and/or configurations disclosed in relation to one embodimentmay be used in other embodiments unless the disclosure explicitly statesotherwise. The scope of the present disclosure should, therefore, bedetermined only by the following claims.

1. A displacement measuring cell comprising: a conductive fluid; astationary electrode electrically coupled to the conductive fluid; amovable electrode electrically and physically coupled to the conductivefluid and configured to move relative to the stationary electrode; andan electrical property measuring device coupled to the movable andstationary electrodes and configured to measure an electrical propertydependent on movement of the movable electrode relative to thestationary electrode.
 2. The displacement measuring cell of claim 1,wherein the conductive fluid is configured to prevent accumulation ofcharge between the movable and stationary electrodes.
 3. Thedisplacement measuring cell of claim 1, wherein the displacementmeasuring cell is configured to change a volume of conductive fluidbetween the stationary and movable electrodes when the movable electrodemoves relative to the stationary electrode.
 4. The displacementmeasuring cell of claim 3, wherein the electrical property measuringdevice is configured to measure changes in an electrical propertyselected from the group consisting of voltage, current, impedance, andresistance when the volume of conductive fluid changes.
 5. Thedisplacement measuring cell of claim 1, wherein the electrical propertymeasuring device is selected from the group consisting of an ohmmeter,an ammeter, a voltmeter, and an analog-to-digital converter.
 6. Thedisplacement measuring cell of claim 1, further comprising a processorconfigured to compute a displacement from an electrical propertymeasurement.
 7. The displacement measuring cell of claim 6, wherein theprocessor is configured to compute at least one of a linear displacementand an angular displacement from the electrical property measurement. 8.The displacement measuring cell of claim 6, wherein the processor isconfigured to calibrate electrical property measurements todisplacements.
 9. The displacement measuring cell of claim 1, furthercomprising a power source, wherein the power source is electricallycoupled with the stationary electrode and electrically coupled with themovable electrode.
 10. The displacement measuring cell of claim 1,wherein the stationary electrode comprises a flat plate.
 11. Thedisplacement measuring cell of claim 1, further comprising a conductivefluid reservoir.
 12. The displacement measuring cell of claim 11,further comprising a pressure controller configured to regulate apressure of the conductive fluid.
 13. The displacement measuring cell ofclaim 1, wherein the conductive fluid is incompressible.
 14. Thedisplacement measuring cell of claim 1, wherein the movable electrode isconfigured to move linearly relative to the stationary electrode. 15.The displacement measuring cell of claim 1, wherein the movableelectrode comprises at least one material selected from the groupconsisting of silver, gallium, conductive ink, and tungsten.
 16. Thedisplacement measuring cell of claim 1, wherein the conductive fluidcomprises at least one material selected from the group consisting ofsodium chloride, potassium chloride, and gallium alloy.
 17. Thedisplacement measuring cell of claim 1, wherein the movable electrode isconfigured to move along a circular path relative to the stationaryelectrode.
 18. The displacement measuring cell of claim 17, furthercomprising: a torus-shaped cavity, wherein the torus-shaped cavitycontains the circular path; an end cap, wherein the stationary electrodeis coupled to the end cap; a piston, wherein the movable electrode iscoupled to the piston, and wherein the piston and the movable electrodeare configured to move along the circular path; and a bladder coupled tothe piston, wherein the bladder is configured to prevent conductivefluid from leaking out of the torus-shaped cavity.
 19. The displacementmeasuring cell of claim 1, further comprising: an end cap, wherein thestationary electrode is coupled to the end cap; a piston assemblycomprising: a piston, wherein the movable electrode is coupled to thepiston; and a piston rod, wherein the piston is coupled to a proximalend of the piston rod.
 20. The displacement measuring cell of claim 19,wherein the piston comprises a nonconductive material.
 21. Thedisplacement measuring cell of claim 19, further comprising a pistonextension chamber and a piston retraction chamber.
 22. The displacementmeasuring cell of claim 21, further comprising a pump configured to addadditional conductive fluid to the piston extension chamber and removeconductive fluid from the piston retraction chamber.
 23. Thedisplacement measuring cell of claim 21, further comprising a pumpconfigured to add additional conductive fluid to the piston retractionchamber and remove conductive fluid from the piston extension chamber.24. The displacement measuring cell of claim 19, further comprising acontact head coupled to a distal end of the piston rod, wherein thecontact head is coupled to a second displacement measuring sensor. 25.The displacement measuring cell of claim 19, further comprising: aprocessor configured to control movement of the piston based on computercode stored in a memory; and an output device configured to outputdisplacement measurements.
 26. The displacement measuring cell of claim19, further comprising: a piston chamber; and a positive displacementpump configured to move the piston by adding or removing a quantity ofthe conductive fluid to the piston chamber, wherein the positivedisplacement pump is insulated from the conductive fluid.
 27. Thedisplacement measuring cell of claim 26, wherein the positivedisplacement pump comprises plastic to insulate the positivedisplacement pump from the conductive fluid.
 28. The displacementmeasuring cell of claim 26, further comprising a valve configured tocontrol flow of the conductive fluid to the piston chamber.
 29. Thedisplacement measuring cell of claim 19, further comprising a bladdercoupled to the piston, wherein the bladder is configured to prevent theconductive fluid from leaking from the displacement measuring cell. 30.The displacement measuring cell of claim 1, further comprising aconformable wall configured to enclose the conductive fluid and themovable and stationary electrodes.
 31. The displacement measuring cellof claim 30, further comprising a shear sensor, wherein the conformablewall further comprises a contact surface, wherein the shear sensor iscoupled to the contact surface, wherein the shear sensor comprises atleast one material selected from the group consisting of apiezoresistive material and a piezoelectric material, wherein thepiezoelectric material comprises a polyvinylidene fluoride (PVDF) film,and wherein the shear sensor is perpendicular to the contact surface.32. The displacement measuring cell of claim 30, wherein the conformablewall comprises silicon.
 33. The displacement measuring cell of claim 1,further comprising: a flexible wall comprising a contact surface; one ormore stationary electrodes in contact with the conductive fluid, whereinthe one or more stationary electrodes include the stationary electrode;and a plurality of movable electrodes coupled to the flexible wall andin contact with the conductive fluid, wherein the plurality of movableelectrodes include the movable electrode; a power source; and a controlcircuit configured to selectively couple and decouple the one or morestationary and movable electrodes from the power source.
 34. Thedisplacement measuring cell of claim 33, wherein the control circuitcomprises a multiplexer.
 35. The displacement measuring cell of claim34, wherein the control circuit is configured to couple at most one ofthe one or more stationary electrodes and at most one of the pluralityof movable electrodes to the power source at any time.
 36. Thedisplacement measuring cell of claim 35, wherein the control circuit isconfigured to enable only directly opposing stationary and movableelectrodes at the same time.
 37. The displacement measuring cell ofclaim 33, wherein the control circuit comprises a plurality oftransistors corresponding to the plurality of movable electrodes,wherein the source of each transistor is electrically coupled with thepower source and the drain of each transistor is electrically coupledwith the corresponding movable electrode.
 38. The displacement measuringcell of claim 33, further comprising an integrated circuit embedded inthe flexible wall, wherein the integrated circuit comprises at least oneof the electrical property measuring device, the control circuit, amultiplexer, and a transistor, and wherein the flexible wall comprises aflexible printed circuit board.
 39. The displacement measuring cell ofclaim 38, wherein the integrated circuit comprises carbon nanotubes. 40.The displacement measuring cell of claim 33, wherein the plurality ofmovable electrodes are embedded in the flexible wall.
 41. Thedisplacement measuring cell of claim 40, wherein the plurality ofmovable electrodes comprise microfluidic channels to enhance electricalcoupling with the conductive fluid.
 42. The displacement measuring cellof claim 1, further comprising a temperature sensor to measure thetemperature of the conductive fluid.
 43. The displacement measuring cellof claim 42, wherein the temperature sensor is in contact with at leastone of a reservoir, a hydraulic line, the movable electrode, thestationary electrode, a chamber containing the movable and stationaryelectrodes, and a portion of the chamber adjacent to a contact surface.44. The displacement measuring cell of claim 1, further comprising ashear sensor selected from the group consisting of a piezoresistivesensor and a polyvinylidene fluoride (PVDF) film sensor, wherein theshear sensor is perpendicular to the movable electrode.
 45. Atouch-sensitive robotic gripping system comprising: a first grippingmember comprising a first plurality of displacement measuring cells,each displacement measuring cell comprising: a conductive fluid, astationary electrode electrically coupled to the conductive fluid, and amovable electrode electrically coupled to the conductive fluid andconfigured to move relative to the stationary electrode; and a firstelectrical property measuring device configured to measure a firstelectrical property while selectively coupled to the stationaryelectrode and the movable electrode of a selected displacement measuringcell, wherein the first electrical property depends on movement of themovable electrode relative to the stationary electrode.
 46. Thetouch-sensitive robotic gripping system of claim 45, further comprising:a processor configured to receive measurements of the first electricalproperty and generate a model of an object being sensed by the firstplurality of displacement measuring cells; and a memory in electricalcommunication with the processor and configured to store themeasurements.
 47. The touch-sensitive robotic gripping system of claim46, wherein the processor is configured to generate the model of theobject by: determining maximum and minimum extension positions during acalibration process; and computing a plurality of differential volumesbased on: differences between current movable electrode positionscomputed from the received measurements and the maximum or the minimumextension positions; and an electrode area of each movable electrode.48. The touch-sensitive robotic gripping system of claim 47, wherein theprocessor is configured to generate a three dimensional model of theobject by assembling the plurality of differential volumes into thethree dimensional model based on known positions of the first pluralityof displacement measuring cells.
 49. The touch-sensitive roboticgripping system of claim 46, wherein the processor is configured to:determine a perimeter of the object from the received measurements; andgenerate a three dimensional representation of the object from thedetermined perimeter.
 50. The touch-sensitive robotic gripping system ofclaim 46, wherein the memory is configured to store a diagram of theobject.
 51. The touch-sensitive robotic gripping system of claim 50,wherein the processor determines at least one of an orientation and alocation of the object being sensed by the first plurality ofdisplacement measuring cells by comparing the model of the object to thediagram of the object.
 52. The touch-sensitive robotic gripping systemof claim 51, further comprising a plurality of servo motors, wherein theplurality of servo motors control movement of the first gripping memberand a second gripping member and the processor instructs the pluralityof servo motors to change the orientation of the object so amanufacturing operation may be performed.
 53. The touch-sensitiverobotic gripping system of claim 52, wherein the processor instructs theplurality of servo motors to change the orientation of the object tomatch a predetermined orientation.
 54. The touch-sensitive roboticgripping system of claim 46, wherein the processor moves the firstgripping member relative to a second gripping member such that thestationary electrode does not touch the movable electrode.
 55. Thetouch-sensitive robotic gripping system of claim 45, wherein the firstplurality of displacement measuring cells is configured in a pluralityof layers, wherein the plurality of layers are mechanically in serieswith each other, and wherein displacement measuring cells within eachlayer are mechanically in parallel with each other.
 56. Thetouch-sensitive robotic gripping system of claim 55, wherein theplurality of layers comprises a final layer comprising pistonlessdisplacement measuring cells comprising flexible walls, and wherein eachlayer other than the final layer comprises displacement measuring cellscomprising pistons.
 57. The touch-sensitive robotic gripping system ofclaim 45, further comprising a pressure monitoring device configured tomeasure a pressure of the conductive fluid.
 58. The touch-sensitiverobotic gripping system of claim 57, further comprising a processorconfigured to move the first gripping member relative to a secondgripping member based on at least one of a pressure measurement and afirst electrical property measurement.
 59. The touch-sensitive roboticgripping system of claim 45, further comprising a second grippingmember, a third gripping member, and a fourth gripping member, whereinthe first gripping member is disposed opposite the second grippingmember, the third gripping member is disposed opposite the fourthgripping member, and the first gripping member is perpendicular to thethird gripping member.
 60. The touch-sensitive robotic gripping systemof claim 45, further comprising: a second gripping member comprising asecond plurality of displacement measuring cells, each displacementmeasuring cell in the second plurality of displacement measuring cellscomprising: a conductive fluid, a stationary electrode electricallycoupled to the conductive fluid, and a movable electrode electricallycoupled to the conductive fluid; and a second electrical propertymeasuring device configured to measure a second electrical property ofan object being sensed while coupled to movable electrodes in at leasttwo different displacement measuring cells.
 61. The touch-sensitiverobotic gripping system of claim 60, wherein the second electricalproperty measuring device is configured to measure a capacitance of theobject.
 62. The touch-sensitive robotic gripping system of claim 61,further comprising a processor configured to compute a dielectricconstant and/or permittivity of the object.
 63. The touch-sensitiverobotic gripping system of claim 62, further comprising a memoryconfigured to store dielectric values and/or permittivity values for oneor more materials, wherein the processor is further configured todetermine a material of the object by comparing the dielectric constantand/or permittivity of the object to the stored dielectric values and/orpermittivity values.
 64. The touch-sensitive robotic gripping system ofclaim 62, wherein the second electrical property measuring device isfurther configured to be calibrated by measuring a capacitance withoutthe object between the movable electrodes.
 65. The touch-sensitiverobotic gripping system of claim 61, wherein the second electricalproperty measuring device is configured to measure a plurality ofcapacitances while electrical power is applied at a correspondingplurality of frequencies and/or amplitudes.
 66. The touch-sensitiverobotic gripping system of claim 60, wherein the second electricalproperty measuring device is configured to measure a dissipation factor.67. The touch-sensitive robotic gripping system of claim 60, wherein thesecond electrical property measuring device is configured to measureresistivity.
 68. The touch-sensitive robotic gripping system of claim60, further comprising a strain gauge, wherein the strain gaugecomprises a beam comprising a length-sensitive electrical resistor. 69.The touch-sensitive robotic gripping system of claim 60, furthercomprising an electrical motor and a lead screw, wherein the electricalmotor and the lead screw are configured to move the second grippingmember.
 70. The touch-sensitive robotic gripping system of claim 60,further comprising a quick-change turret to perform one or moreoperations on the object.
 71. The touch-sensitive robotic grippingsystem of claim 70, wherein the quick-change turret determines whichoperation to perform based on at least one of the first electricalproperty and the second electrical property.
 72. The touch-sensitiverobotic gripping system of claim 70, wherein the quick-change turretcomprises a rotary joint.
 73. The touch-sensitive robotic grippingsystem of claim 60, further comprising a cam guide configured to movethe second gripping member.
 74. The touch-sensitive robotic grippingsystem of claim 45, further comprising: a second gripping membercomprising a second plurality of displacement measuring cells, eachdisplacement measuring cell in the second plurality of displacementmeasuring cells comprising: a conductive fluid, a stationary electrodeelectrically coupled to the conductive fluid, and a movable electrodeelectrically coupled to the conductive fluid, wherein each displacementmeasuring cell in the first and second pluralities of displacementmeasuring cells further comprises: a wall enclosing the conductivefluid, the stationary electrode, and the movable electrode; and anexternal electrode attached to an outside of the wall; and a secondelectrical property measuring device configured to measure a secondelectrical property of the object while coupled to external electrodesin at least two different displacement measuring cells.
 75. Thetouch-sensitive robotic gripping system of claim 74, wherein the secondelectrical property measuring device is configured to measureresistance.
 76. The touch-sensitive robotic gripping system of claim 75,further comprising a processor configured to compute a resistivity ofthe object.
 77. The touch-sensitive robotic gripping system of claim 76,further comprising a memory configured to store resistivity values forone or more materials, wherein the processor is further configured todetermine a material of the object by comparing the resistivity of theobject to the stored resistivity values.
 78. The touch-sensitive roboticgripping system of claim 76, wherein the second electrical propertymeasuring device is further configured to be calibrated by measuring aresistance without the object between the first external electrode andthe second external electrode.
 79. The touch-sensitive robotic grippingsystem of claim 45, wherein the first gripping member comprises a footcomprising: the first plurality of displacement measuring cells; apressure sensor configured to measure a fluid pressure of the conductivefluid; one or more shear sensors configured to measure a shear forceagainst a bottom of the foot; and a processor configured to determine atleast one of a robot weight and a robot load from at least one of thefluid pressure and a plurality of displacement measurements from thefirst plurality of displacement measuring cells, wherein the firstplurality of displacement measuring cells are configured to support thefoot and measure the contour of the ground.
 80. A method of gripping anobject using a touch-sensitive robotic gripper, the method comprising:providing a first gripping member comprising a plurality of layersincluding one or more non-final layers and a final layer configured tocontact the object, each layer comprising one or more displacementmeasuring cells, each displacement measuring cell in each layercomprising: a conductive fluid, a stationary electrode in contact withthe conductive fluid, and a movable electrode in contact with theconductive fluid, wherein each displacement measuring cell in the one ormore non-final layers comprises a piston assembly comprising: a piston,wherein the movable electrode is coupled to the piston, a piston rod,wherein a proximal end of the piston rod is coupled to the piston, and acontact head, wherein the contact head is coupled to a distal end of thepiston rod; retracting each piston to a minimum extension position;extending the piston in each displacement measuring cell in eachnon-final layer until the conductive fluid reaches a predeterminedpressure; and calculating a total distance travelled for eachdisplacement measuring cell in the final layer, wherein the totaldistance travelled for a particular displacement measuring cell is adistance travelled by the movable electrode in the particulardisplacement measuring cell plus distances travelled by movableelectrodes in displacement measuring cells mechanically in series withthe particular displacement measuring cell.
 81. The method of claim 80,wherein extending the piston in each displacement measuring cellcomprises extending the piston in each displacement measuring cell ineach non-final layer simultaneously.
 82. The method of claim 81, whereinextending the piston in each displacement measuring cell comprisesextending the piston in each displacement measuring cell with a commonpump and a common control valve.
 83. The method of claim 82, whereinextending the piston in each displacement measuring cell with a commonpump comprises controlling the common pump based on measurements frompressure sensors hydraulically coupled to the pump.
 84. The method ofclaim 80, wherein extending the piston in each displacement measuringcell comprises extending the piston in each displacement measuring cellin each non-final layer until the conductive fluid reaches apredetermined pressure once each piston in a preceding layer hasfinished extending.
 85. The method of claim 80, further comprisinginitial calibrating steps of: providing a second gripping member;retracting each piston to the minimum extension position; extending eachpiston until each contact head in the final layer touches the secondgripping member to obtain a maximum extension position; and mapping theminimum and maximum extension positions to displacements.
 86. The methodof claim 85, wherein mapping comprises associating measurements of anelectrical characteristic with the minimum and maximum extensionpositions.
 87. The method of claim 86, wherein the electricalcharacteristic is selected from the group consisting of a voltage, acurrent, an impedance, and a resistance.
 88. The method of claim 85,wherein mapping the minimum and maximum extension positions todisplacements comprises mapping the minimum and maximum extensionpositions to discrete values, and wherein a minimum discrete incrementcorresponds to a desired displacement measurement resolution.
 89. Themethod of claim 85, wherein mapping the minimum and maximum extensionpositions to displacements comprises defining a function or curvemapping electrical property measurements to displacements.
 90. Themethod of claim 89, wherein the function or curve is configured toreceive a temperature measurement as input and output atemperature-corrected displacement.
 91. The method of claim 80, whereinretracting each piston comprises adding conductive fluid to a pistonretraction chamber. 92.-142. (canceled)